Low Tire Pressure Indicator Always On
Low Tire Pressure Indicator Always On
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.
Circuit/System Description
The remote control door lock receiver (RCDLR) receives a radio frequency (RF) transmission from each tire pressure sensor. Each sensor RF transmission contains its own unique identification (ID) code that must be learned into the RCDLR memory. Once all 4 IDs have been learned and vehicle speed is greater than 40 km/h (25 mph), the RCDLR continuously compares IDs in received transmission to its learned IDs to determine if all 4 sensors are present. If the RCDLR detects a low tire pressure condition or a malfunction in the system, it will send a serial data message to the instrument panel cluster (IPC) requesting tire pressure monitor indicator illumination and to display a data message on the driver information center (DIC), if equipped.
Diagnostic Aids
* Some aftermarket wheel valve stem holes are located further from the wheel rim than original equipment wheels. When using the TPM special tool to activate a sensor, ensure the tool antenna is no further than 15 cm (6 in) from the sensor and is aiming upward.
* Aftermarket wheel value stem locations can cause a sensor to not function correctly.
* A sensor may have been damaged due to a previous wheel/tire service or flat tire event.
* The use of tire sealants can obstruct the sensor pressure sensing port and cause inaccurate tire pressure readings. If this condition is verified, remove the sealer from the tire and replace the sensor. Refer to Tire Pressure Indicator Sensor Replacement (Tire Pressure Indicator Sensor Replacement) .
* Occasionally sensor transmissions are not received by the RCDLR due to vehicle level RF interference from items such as but not limited to aftermarket ignition systems, DVD players, CB radios, or metallic type window tinting.
* The sensor activation procedure may have to be repeated up to 3 times before determining a sensor is malfunctioning. In the event a particular sensor's information is displayed on the special tool upon activation but the horn does not chirp, it may be necessary to rotate the wheel valve stem to a different position due to the RF signal is being blocked by another component.
* Occasionally sensors can become mislocated due to previous tire rotations where the sensor learn procedure was not performed or stray sensor transmissions have been received from other vehicles. Always learn the sensors to ensure the DTC set is for that actual physical corner of the vehicle. Refer to Tire Pressure Sensor Learn (Programming and Relearning) .
Reference Information
Description and Operation
Tire Pressure Monitor Description and Operation (Description and Operation)
Electrical Information Reference
* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Special Tools
J-46079 Tire Pressure Monitor Diagnostic Tool
Circuit/System Verification
Important: When a TPM DTC is set, the tire pressure monitor indicator icon will flash for 1 minute after the IPC bulb check is completed and then remains illuminated. If equipped with a DIC, a service tire monitor type message will also be displayed.
Low tire pressure in one or more tires is indicated by a continuously illuminated tire pressure monitor indicator icon after the IPC bulb check is completed. If equipped with a DIC, a check tire pressure type message will also be displayed.
1. Verify all tires are inflated to the proper pressure ± 10 percent. Refer to Vehicle Certification, Tire Placard, Anti-Theft, and Service Parts ID Label (Application and ID) .
• If not within the specified range, adjust all tire pressures to specification and drive the vehicle over 40 km/h (25 mph) for greater than 2 minutes. The tire pressure monitor indicator icon should turn OFF.
2. Using the J-46079 , activate each tire pressure sensor and record each sensors tire pressure reading. Check the tire pressures with a known accurate hand held tire pressure gauge. Verify that the pressure readings from the special tool do not differ more than 27.6 kPa (4 psi) from the actual tire pressure readings.
• If not within the specified range, replace the suspect tire pressure sensor.
3. Using a scan tool, enable the TPM learn mode. Use the J-46079 in simulate mode to learn 4 simulated sensor transmissions into the RCDLR. Observe tire pressures in the scan tool data display. Verify the simulated tire pressures do not differ more than +/-27.6 kPa (4 psi) of the scan tool reading.
• If not within the specified range, replace the RCDLR.
4. Using a scan tool, select instrument panel special functions Lamp Test. Command the instrument panel warning lamps OFF. Verify the tire pressure monitor indicator icon turns OFF.
• If the tire pressure monitor icon does not turn OFF, replace the IPC.
5. Ignition ON, use the scan tool to setup the Tire Type/Pressure Selection in the RCDLR Module Setup menu. Refer to the Vehicle Certification, Tire Placard, Anti-Theft, and Service Parts ID Label (Application and ID) . Verify the tire pressure monitor indicator icon turns OFF.
• If the tire pressure monitor icon does not turn OFF, replace the RCDLR.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Tire Pressure Indicator Sensor Replacement (Tire Pressure Indicator Sensor Replacement)
* Tire Pressure Sensor Learn (Programming and Relearning)
* Control Module References (Programming and Relearning) for IPC or RCDLR replacement, setup, and programming