DTC Chart(s)
Diagnostics in this manual assume a certain skill level and knowledge of Ford-specific diagnostic practices.
REFER to: Diagnostic Methods (100-00 General Information, Description and Operation).
PAM DTC Chart
| DTC | Description | Action |
|---|---|---|
| B129C:12 | Left Front Side Sensor: Circuit Short To Battery | GO to Pinpoint Test A |
| B129C:14 | Left Front Side Sensor: Circuit Short To Ground or Open | GO to Pinpoint Test B |
| B129C:96 | Left Front Side Sensor: Component Internal Failure | GO to Pinpoint Test C |
| B129D:12 | Right Front Side Sensor: Circuit Short To Battery | GO to Pinpoint Test A |
| B129D:14 | Right Front Side Sensor: Circuit Short To Ground or Open | GO to Pinpoint Test B |
| B129D:96 | Right Front Side Sensor: Component Internal Failure | GO to Pinpoint Test C |
| B129E:11 | Enable/Disable Switch - Semi-automatic Advanced Parallel Park : Circuit Short To Ground | GO to Pinpoint Test G |
| B13F3:12 | Left Rear Side Sensor: Circuit Short To Battery | GO to Pinpoint Test D |
| B13F3:14 | Left Rear Side Sensor: Circuit Short To Ground or Open | GO to Pinpoint Test E |
| B13F3:96 | Left Rear Side Sensor: Component Internal Failure | GO to Pinpoint Test F |
| B13F4:12 | Right Rear Side Sensor: Circuit Short To Battery | GO to Pinpoint Test D |
| B13F4:14 | Right Rear Side Sensor: Circuit Short To Ground or Open | GO to Pinpoint Test E |
| B13F4:96 | Right Rear Side Sensor: Component Internal Failure | GO to Pinpoint Test F |
| All other PAM Diagnostic Trouble Codes (DTCs) | - |
REFER to: Parking Aid (413-13A Parking Aid, Diagnosis and Testing). |
Symptom Chart(s)
Diagnostics in this manual assume a certain skill level and knowledge of Ford-specific diagnostic practices.
REFER to: Diagnostic Methods (100-00 General Information, Description and Operation).
Symptom Chart: Active Park Assist
| Condition | Possible Causes | Actions |
|---|---|---|
| A module does not communicate with the diagnostic scan tool |
|
REFER to: Communications Network (418-00 Module Communications Network, Diagnosis and Testing). |
| The active park assist system does not activate when the active park assist switch is pressed | Refer to the Pinpoint Test | GO to Pinpoint Test G |
| The centerstack infotainment display and/or the IPC message center display shows an active park assist fault message | Refer to the Pinpoint Test | GO to Pinpoint Test H |
| The centerstack infotainment display shows the active park assist not available message |
|
The active park assist system is not available if the AdvanceTrac® is off or if an ABS or AdvanceTrac® event is in progress when the system is being activated by the driver. |
|
The active park assist system is not available immediately after a battery disconnect or if the PSCM and/or the ABS module were recently reprogrammed. PERFORM the following: drive the vehicle straight on a flat/smooth road above 20 km/h (12mph) with minimal driver steering input for 30 seconds. Abort this step at any time to maintain safe driving, and repeat the process if required. If completed correctly, active park assist will be available upon pressing the active park assist switch. | |
| The active park assist system does not position the vehicle correctly |
|
REMOVE and correctly INSTALL the active park assist sensor(s) as necessary. REFER to: Front Active Park Assist Sensors (413-13B Parking Aid - Vehicles With: Active Park Assist, Removal and Installation). REFER to: Rear Active Park Assist Sensors (413-13B Parking Aid - Vehicles With: Active Park Assist, Removal and Installation). |
|
CLEAN the bumper covers and active park assist sensors with high-pressure water. | |
|
The temperature of the air around the vehicle can change rapidly, such as the vehicle being driven into or out of a parking garage or car wash. As a result, the air temperature displayed in the vehicle may not be close enough to the actual ambient air temperature. The active park assist system relies on accurately sensing the ambient air temperature to compensate the sensors. No action is required. | |
|
INSPECT the tire condition, pressure and size. A considerably worn tire positions the vehicle far from the curb. A larger size tire positions the vehicle closer to the curb. REPAIR or REPLACE tire(s) as necessary. | |
|
INFORM the customer not to allow the vehicle to roll in the opposite direction when operating the active park assist system. REFER to the Owner's Literature. | |
|
The system may not be able to align the vehicle to curbs that are damaged, very shallow or covered by debris. If this is the circumstance, the system aligns the vehicle relative to objects bordering the parking space. | |
|
The system aligns the vehicle to the objects bordering the parking space when a curb is not detected. | |
|
Elevated attachments may not be detected by the system. | |
|
The system scans the parking space as the vehicle is driven by the available spaces. Therefore, the system cannot detect if the parked vehicle or objects position has changed after the parking space has been scanned. No action needs to take place at this time. | |
|
INFORM the customer to allow for the steering wheel to complete its rotation before moving the vehicle after a gear change. | |
| The active park assist system does not position the vehicle correctly (continued) |
|
INSTALL a new active park assist sensor(s) as necessary. REFER to: Front Active Park Assist Sensors (413-13B Parking Aid - Vehicles With: Active Park Assist, Removal and Installation). REFER to: Rear Active Park Assist Sensors (413-13B Parking Aid - Vehicles With: Active Park Assist, Removal and Installation). |
| The active park assist system does not offer available parking spaces |
|
The vehicle must be driven greater than 40 cm (16 in) and less than 152 cm (60 in) from the adjacent vehicle. |
|
|
|
|
There needs to be enough space on the opposite side of the vehicle to allow the front of the vehicle to swing out as the operator backs into the space. | |
|
INSPECT and CLEAN the active park assist sensor(s). REMOVE any obstruction that is covering the sensor(s). | |
|
INSTALL a new active park assist sensor. REFER to: Front Active Park Assist Sensors (413-13B Parking Aid - Vehicles With: Active Park Assist, Removal and Installation). REFER to: Rear Active Park Assist Sensors (413-13B Parking Aid - Vehicles With: Active Park Assist, Removal and Installation). |
|
|
DRIVE the vehicle to allow airflow over the Outside Air Temperature (OAT) sensors until the centerstack infotainment display temperature reading is reflective of the actual outside ambient temperature. | |
| The centerstack infotainment display shows POA NOT AVAILABLE when the turn signal is used during a parallel park out assist maneuver |
|
The active park assist system only offers the parallel park out assist feature when the occupied parking space is at least 1.2 times the length of the vehicle. The system is operating correctly at this time. |
|
INSPECT and CLEAN the front active park assist sensor(s). REMOVE any obstruction that is covering the sensor(s). | |
|
The parallel park out assist feature is only available when an object or vehicle is detected within 2 m (7 ft) of either the front or the rear bumper. The system is operating correctly at this time. | |
|
The parallel park out assist feature displays the message POA NOT AVAILABLE when objects or vehicles are detected within 110 cm (4 ft) in North America and South America or detected within 60 cm (2 ft) in Asia Pacific on the side of turn signal activation. Passing traffic, pedestrians or other objects may be detected. When the turn signal is activated, VERIFY the desired side has a clearance of at least 110 cm (4 ft) in North America and South America or 60 cm (2 ft) in Asia Pacific. | |
| The active park assist system does not offer the parallel park out assist feature | The vehicle has been driven farther than 2 m (7 ft) after ignition on, or after a parallel park. | INFORM customer that the parallel park out assist feature is only an available option immediately after a successful automated parallel park or immediately after ignition on. Driving farther than 2 m (7 ft) after either of these events results in the parallel park out assist not being an available option for the driver to select. |
Pinpoint Test(s)
DTC B129C:12, DTC B129D:12
Refer to Wiring Diagrams Cell 131 for schematic and connector information.
Normal Operation and Fault Conditions
REFER to: Parking Aid - System Operation and Component Description (413-13B Parking Aid - Vehicles With: Active Park Assist, Description and Operation).
DTC Fault Trigger Conditions
| DTC | Description | Fault Trigger Conditions |
|---|---|---|
| B129C:12 | Left Front Side Sensor: Circuit Short To Battery | A continuous and on-demand DTC that sets in the PAM when the left front active park assist sensor signal circuit is shorted to battery voltage. |
| B129D:12 | Right Front Side Sensor: Circuit Short To Battery | A continuous and on-demand DTC that sets in the PAM when the right front active park assist sensor signal circuit is shorted to battery voltage. |
Possible Causes
NOTE: Before disconnecting any of the active park assist sensors, verify the connectors are properly seated and latched.
| A1 CHECK THE DIAGNOSTIC TROUBLE CODES (DTCS) FROM THE PAM (PARKING ASSIST CONTROL MODULE) SELF-TEST | ||||||||||||||||
Are multiple front parking aid sensor Diagnostic Trouble Codes (DTCs) recorded?
|
||||||||||||||||
| A2 CHECK THE FRONT BUMPER WIRING HARNESS | ||||||||||||||||
Is the front bumper wiring harness OK?
|
||||||||||||||||
| A3 CHECK THE SENSOR SIGNAL RETURN CIRCUIT FOR A SHORT TO VOLTAGE | ||||||||||||||||
Is any voltage present?
|
||||||||||||||||
| A4 CHECK THE SENSOR VOLTAGE SUPPLY AND SIGNAL RETURN CIRCUITS FOR A SHORT TOGETHER | ||||||||||||||||
Is the resistance greater than 10,000 ohms?
|
||||||||||||||||
| A5 CHECK THE FRONT ACTIVE PARK ASSIST SENSOR | ||||||||||||||||
Is DTC B129C:12 or DTC B129D:12 still present?
|
||||||||||||||||
| A6 CHECK FOR CORRECT BCM (BODY CONTROL MODULE) OPERATION | ||||||||||||||||
Is the concern still present?
|
DTC B129C:14, DTC B129D:14
Refer to Wiring Diagrams Cell 131 for schematic and connector information.
Normal Operation and Fault Conditions
REFER to: Parking Aid - System Operation and Component Description (413-13B Parking Aid - Vehicles With: Active Park Assist, Description and Operation).
DTC Fault Trigger Conditions
| DTC | Description | Fault Trigger Conditions |
|---|---|---|
| B129C:14 | Left Front Side Sensor: Circuit Short To Ground Or Open | A continuous and on-demand DTC that sets in the PAM when any of the left front active park assist sensor circuits are open or the sensor signal line is shorted to ground. |
| B129D:14 | Right Front Side Sensor: Circuit Short To Ground Or Open | A continuous and on-demand DTC that sets in the PAM when any of the right front active park assist sensor circuits are open or the sensor signal line is shorted to ground. |
Possible Causes
NOTE: Before disconnecting any of the active park assist sensors, verify the connectors are properly seated and latched.
| B1 CHECK THE DIAGNOSTIC TROUBLE CODES (DTCS) FROM THE PAM (PARKING ASSIST CONTROL MODULE) SELF-TEST | ||||||||||||||||||||||||||||
Are multiple front parking aid sensor Diagnostic Trouble Codes (DTCs) recorded?
|
||||||||||||||||||||||||||||
| B2 CHECK THE FRONT BUMPER WIRING HARNESS | ||||||||||||||||||||||||||||
Is the front bumper wiring harness OK?
|
||||||||||||||||||||||||||||
| B3 CHECK THE SENSOR CIRCUITS FOR OPENS | ||||||||||||||||||||||||||||
Are the resistances less than 3 ohms?
|
||||||||||||||||||||||||||||
| B4 CHECK THE SENSOR SIGNAL RETURN CIRCUIT FOR A SHORT TO GROUND | ||||||||||||||||||||||||||||
Is the resistance greater than 10,000 ohms?
|
||||||||||||||||||||||||||||
| B5 CHECK THE FRONT ACTIVE PARK ASSIST SENSOR | ||||||||||||||||||||||||||||
Is DTC B129C:14 or DTC B129D:14 still present?
|
||||||||||||||||||||||||||||
| B6 CHECK FOR CORRECT BCM (BODY CONTROL MODULE) OPERATION | ||||||||||||||||||||||||||||
Is the concern still present?
|
DTC B129C:96, DTC B129D:96
Normal Operation and Fault Conditions
REFER to: Parking Aid - System Operation and Component Description (413-13B Parking Aid - Vehicles With: Active Park Assist, Description and Operation).
DTC Fault Trigger Conditions
| DTC | Description | Fault Trigger Conditions |
|---|---|---|
| B129C:96 | Left Front Side Sensor: Component Internal Failure | A continuous and on-demand DTC that sets in the PAM when the left front active park assist sensor has internally failed or has an incorrect attenuation time. |
| B129D:96 | Right Front Side Sensor: Component Internal Failure | A continuous and on-demand DTC that sets in the PAM when the right front active park assist sensor has internally failed or has an incorrect attenuation time. |
Possible Causes
NOTE: Before disconnecting any of the active park assist sensors, verify the connectors are properly seated and latched.
| C1 CHECK THE CONTINUOUS AND ON-DEMAND PAM (PARKING ASSIST CONTROL MODULE) DIAGNOSTIC TROUBLE CODES (DTCS) | ||||
Are Diagnostic Trouble Codes (DTCs) other than DTC B129C:96 or DTC B129D:96 present?
|
||||
| C2 CHECK THE FRONT ACTIVE PARK ASSIST SENSOR OPERATION | ||||
Does the system pass the azimuth system check?
|
||||
| C3 INSTALL A KNOWN GOOD SENSOR | ||||
Is DTC B129C:96 or DTC B129D:96 still present?
|
||||
| C4 CHECK FOR CORRECT BCM (BODY CONTROL MODULE) OPERATION | ||||
Is the concern still present?
|
DTC B13F3:12, DTC B13F4:12
Refer to Wiring Diagrams Cell 131 for schematic and connector information.
Normal Operation and Fault Conditions
REFER to: Parking Aid - System Operation and Component Description (413-13B Parking Aid - Vehicles With: Active Park Assist, Description and Operation).
DTC Fault Trigger Conditions
| DTC | Description | Fault Trigger Conditions |
|---|---|---|
| B13F3:12 | Left Rear Side Sensor: Circuit Short To Battery | A continuous and on-demand DTC that sets in the PAM when the left rear active park assist sensor signal circuit is shorted to battery voltage. |
| B13F4:12 | Right Rear Side Sensor: Circuit Short To Battery | A continuous and on-demand DTC that sets in the PAM when the right rear active park assist sensor signal circuit is shorted to battery voltage. |
Possible Causes
NOTE: Before disconnecting any of the active park assist sensors, verify the connectors are properly seated and latched.
| D1 CHECK THE DIAGNOSTIC TROUBLE CODES (DTCS) FROM THE PAM (PARKING ASSIST CONTROL MODULE) SELF-TEST | ||||||||||||||||
Are multiple rear parking aid sensor Diagnostic Trouble Codes (DTCs) recorded?
|
||||||||||||||||
| D2 CHECK THE REAR BUMPER WIRING HARNESS | ||||||||||||||||
Is the rear bumper wiring harness OK?
|
||||||||||||||||
| D3 CHECK THE SENSOR SIGNAL RETURN CIRCUIT FOR A SHORT TO VOLTAGE | ||||||||||||||||
Is any voltage present?
|
||||||||||||||||
| D4 CHECK THE SENSOR VOLTAGE SUPPLY AND SIGNAL RETURN CIRCUITS FOR A SHORT TOGETHER | ||||||||||||||||
Is the resistance greater than 10,000 ohms?
|
||||||||||||||||
| D5 CHECK THE REAR ACTIVE PARK ASSIST SENSOR | ||||||||||||||||
Is DTC B13F3:12 or DTC B13F4:12 still present?
|
||||||||||||||||
| D6 CHECK FOR CORRECT BCM (BODY CONTROL MODULE) OPERATION | ||||||||||||||||
Is the concern still present?
|
DTC B13F3:14, DTC B13F4:14
Refer to Wiring Diagrams Cell 131 for schematic and connector information.
Normal Operation and Fault Conditions
REFER to: Parking Aid - System Operation and Component Description (413-13B Parking Aid - Vehicles With: Active Park Assist, Description and Operation).
DTC Fault Trigger Conditions
| DTC | Description | Fault Trigger Conditions |
|---|---|---|
| B13F3:14 | Left Rear Side Sensor: Circuit Short To Ground or Open | A continuous and on-demand DTC that sets in the PAM when any of the left rear active park assist sensor circuits are open or the sensor signal line is shorted to ground. |
| B13F4:14 | Right Rear Side Sensor: Circuit Short To Ground or Open | A continuous and on-demand DTC that sets in the PAM when any of the right rear active park assist sensor circuits are open or the sensor signal line is shorted to ground. |
Possible Causes
NOTE: Before disconnecting any of the active park assist sensors, verify the connectors are properly seated and latched.
| E1 CHECK THE DIAGNOSTIC TROUBLE CODES (DTCS) FROM THE PAM (PARKING ASSIST CONTROL MODULE) SELF-TEST | ||||||||||||||||||||||||||||
Are multiple rear parking aid sensor Diagnostic Trouble Codes (DTCs) recorded?
|
||||||||||||||||||||||||||||
| E2 CHECK THE REAR BUMPER WIRING HARNESS | ||||||||||||||||||||||||||||
Is the rear bumper wiring harness OK?
|
||||||||||||||||||||||||||||
| E3 CHECK THE SENSOR CIRCUITS FOR OPENS | ||||||||||||||||||||||||||||
Are the resistances less than 3 ohms?
|
||||||||||||||||||||||||||||
| E4 CHECK THE SENSOR SIGNAL RETURN CIRCUIT FOR A SHORT TO GROUND | ||||||||||||||||||||||||||||
Is the resistance greater than 10,000 ohms?
|
||||||||||||||||||||||||||||
| E5 CHECK THE REAR ACTIVE PARK ASSIST SENSOR | ||||||||||||||||||||||||||||
Is DTC B13F3:14 or DTC B13F4:14 still present?
|
||||||||||||||||||||||||||||
| E6 CHECK FOR CORRECT BCM (BODY CONTROL MODULE) OPERATION | ||||||||||||||||||||||||||||
Is the concern still present?
|
DTC B13F3:96, DTC B13F4:96
Normal Operation and Fault Conditions
REFER to: Parking Aid - System Operation and Component Description (413-13B Parking Aid - Vehicles With: Active Park Assist, Description and Operation).
DTC Fault Trigger Conditions
| DTC | Description | Fault Trigger Conditions |
|---|---|---|
| B13F3:96 | Left Rear Side Sensor: Component Internal Failure | A continuous and on-demand DTC that sets in the PAM when the left rear active park assist sensor has internally failed or has an incorrect attenuation time. |
| B13F4:96 | Right Rear Side Sensor: Component Internal Failure | A continuous and on-demand DTC that sets in the PAM when the right rear active park assist sensor has internally failed or has an incorrect attenuation time. |
Possible Causes
NOTE: Before disconnecting any of the active park assist sensors, verify the connectors are properly seated and latched.
| F1 CHECK THE CONTINUOUS AND ON-DEMAND PAM (PARKING ASSIST CONTROL MODULE) DIAGNOSTIC TROUBLE CODES (DTCS) | ||||
Are Diagnostic Trouble Codes (DTCs) other than DTC B13F3:96 or DTC B13F4:96 present?
|
||||
| F2 CHECK THE REAR ACTIVE PARK ASSIST SENSOR OPERATION | ||||
Does the system pass the azimuth system check?
|
||||
| F3 INSTALL A KNOWN GOOD SENSOR | ||||
Is DTC B13F3:96 or DTC B13F4:96 still present?
|
||||
| F4 CHECK FOR CORRECT BCM (BODY CONTROL MODULE) OPERATION | ||||
Is the concern still present?
|
The Active Park Assist System Does Not Activate When The Active Park Assist Switch Is Pressed
Normal Operation and Fault Conditions
To
activate, the active park assist system relies on several messaged
inputs and driver input through the active park assist switch.
REFER to: Parking Aid - System Operation and Component Description (413-13B Parking Aid - Vehicles With: Active Park Assist, Description and Operation).
DTC Fault Trigger Conditions
| DTC | Description | Fault Trigger Conditions |
|---|---|---|
| B129E:11 | Enable/Disable Switch - Semi-automatic Advanced Parallel Park : Circuit Short To Ground | A continuous and on-demand DTC that sets in the PAM detects a stuck closed active park assist switch or a short to ground on the active park assist switch input circuit. |
Possible Causes
| G1 VERIFY THE CUSTOMER CONCERN | ||||||||||
Does the active park assist system operate correctly?
|
||||||||||
| G2 CHECK THE PAM (PARKING ASSIST CONTROL MODULE) MODULE DIAGNOSTIC TROUBLE CODES (DTCS) | ||||||||||
Are any Diagnostic Trouble Codes (DTCs) present other than DTC B129E:11?
|
||||||||||
| G3 CHECK THE ACTIVE PARK ASSIST SWITCH CIRCUIT FOR A SHORT TO GROUND | ||||||||||
Is the resistance greater than 10,000 ohms?
|
||||||||||
| G4 CHECK THE ACTIVE PARK ASSIST SWITCH CIRCUIT FOR AN OPEN | ||||||||||
Is the resistance less than 3 ohms?
|
||||||||||
| G5 CHECK THE ACTIVE PARK ASSIST SWITCH GROUND CIRCUIT FOR AN OPEN | ||||||||||
Is the resistance less than 3 ohms?
|
||||||||||
| G6 CHECK THE ACTIVE PARK ASSIST SYSTEM SWITCH OPERATION | ||||||||||
Is the resistance less than 3 ohms with the switch pressed and greater than 10,000 ohms with the switch released?
|
||||||||||
| G7 CHECK FOR CORRECT BCM (BODY CONTROL MODULE) OPERATION | ||||||||||
Is the concern still present?
|
There Is An Active Park Assist Fault Message Shown In The Centerstack Infotainment Display And/Or In The IPC Message Center Display
Refer to Wiring Diagrams Cell 131 for schematic and connector information.
Refer to Wiring Diagrams Cell 14 for schematic and connector information.
Normal Operation and Fault Conditions
REFER to: Parking Aid - System Operation and Component Description (413-13B Parking Aid - Vehicles With: Active Park Assist, Description and Operation).
Possible Causes
| H1 PERFORM A NETWORK TEST | ||||
Do all modules pass the network test?
|
||||
| H2 CHECK THE PAM (PARKING ASSIST CONTROL MODULE) DIAGNOSTIC TROUBLE CODES (DTCS) | ||||
Are any Diagnostic Trouble Codes (DTCs) present?
|
||||
| H3 CHECK THE PSCM (POWER STEERING CONTROL MODULE) DIAGNOSTIC TROUBLE CODES (DTCS) | ||||
Are any Diagnostic Trouble Codes (DTCs) present?
|
||||
| H4 CHECK THE SCCM (STEERING COLUMN CONTROL MODULE) DIAGNOSTIC TROUBLE CODES (DTCS) | ||||
Are any Diagnostic Trouble Codes (DTCs) present?
|
||||
| H5 CHECK THE ABS (ANTI-LOCK BRAKE SYSTEM) MODULE DIAGNOSTIC TROUBLE CODES (DTCS) | ||||
Are any Diagnostic Trouble Codes (DTCs) present?
|
||||
| H6 CHECK THE PCM (POWERTRAIN CONTROL MODULE) DIAGNOSTIC TROUBLE CODES (DTCS) | ||||
Are any Diagnostic Trouble Codes (DTCs) present?
|
||||
| H7 CHECK THE RCM (RESTRAINTS CONTROL MODULE) DIAGNOSTIC TROUBLE CODES (DTCS) | ||||
Are any Diagnostic Trouble Codes (DTCs) present?
|
||||
| H8 CHECK THE IPC (INSTRUMENT PANEL CLUSTER) DIAGNOSTIC TROUBLE CODES (DTCS) | ||||
Are any Diagnostic Trouble Codes (DTCs) present?
|
||||
| H9 CHECK THE GWM (GATEWAY MODULE A) CONTINUOUS MEMORY DIAGNOSTIC TROUBLE CODES (CMDTCS) | ||||
Are any Diagnostic Trouble Codes (DTCs) present?
|
||||
| H10 CHECK THE BCM (BODY CONTROL MODULE) DIAGNOSTIC TROUBLE CODES (DTCS) | ||||
Are any Diagnostic Trouble Codes (DTCs) present?
|
||||
| H11 CHECK THE APIM (SYNC MODULE) DIAGNOSTIC TROUBLE CODES (DTCS) | ||||
Are any Diagnostic Trouble Codes (DTCs) present?
|
||||
| H12 CHECK FOR CORRECT BCM (BODY CONTROL MODULE) OPERATION | ||||
Is the concern still present?
|
Azimuth System Check. General Procedures
The tire pressure monitoring system measures pressure in your road tires and sends the tire pressure readings to your vehicle. You can view the tire pressure readings through the information display. The low tire pressure warning light will turn on if the tire pressure is significantly low. Once the light is illuminated, your tires are under-inflated and need to be inflated to the manufacturer’s recommended tire pressure. Even if the light turns on and a short time later turns off, your tire pressure still needs to be checked.