With RPO UH3
DTC C0750, C0755, C0760, or C0765 (with UH3)
(RPO UH3 - Indicator Low Tire Pressure, Var 2)
Diagnostic Instructions
• Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Diagnostic System Check - Vehicle
• Review Strategy Based Diagnosis for an overview of the diagnostic approach. Strategy Based Diagnosis
• Diagnostic Procedure Instructions provides an overview of each diagnostic category. Diagnostic Procedure Instructions
DTC Descriptors
DTC C0750: Left Front Low Tire Pressure Sensor
DTC C0755: Right Front Low Tire Pressure Sensor
DTC C0760: Left Rear Low Tire Pressure Sensor
DTC C0765: Right Rear Low Tire Pressure Sensor
Diagnostic Fault Information
Circuit/System Description
The tire pressure monitor (TPM) system has a radio frequency (RF) transmitting pressure sensor in each wheel/tire assembly. As vehicle speed increases, centrifugal force closes the sensor internal roll switch, which puts the sensor into drive mode. The sensor signals are received by the tire pressure receivers mounted near each wheel. Each receiver has a 5 volt reference circuit, a low reference circuit, and signal circuit connected to the tire pressure module. The tire pressure module transmits the individual sensor signals to the remote control door lock receiver (RCDLR) which translates the data contained in the tire pressure sensor RF transmissions into sensor presence, sensor mode, and tire pressure. Once vehicle speed is 40 kph (25 mph) or greater, the RCDLR waits for the sensors to go into Rolling mode. If one or more sensors do not go into Rolling mode, or do not transmit at all, the RCDLR will set DTC C0750, C0755, C0760, or C0765 respectively.
Conditions for Running the DTC
Vehicle speed is 25 mph or greater for 2 minutes.
Conditions for Setting the DTC
• A sensor does not transmit for 18 minutes.
• A receiver does not receive a sensor signal after 18 minutes.
• A malfunctioning tire pressure receiver.
• An open/high resistance, short to voltage, or short to ground in the tire pressure module power or ground circuit.
• An open, short to voltage, short to ground, or high resistance in a tire pressure receiver 5 volt reference, low reference, or signal circuit.
Action Taken When the DTC Sets
• The driver information center (DIC) displays the suspect tire pressure as dashes.
• The driver information center displays the service tire monitor type message.
Conditions for Clearing the DTC
• A current DTC will clear when the malfunction is no longer present and 1 ignition cycle occurs.
• The RCDLR automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.
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 tools antenna is no further than 15 cm (6 in) from the sensor.
• Aftermarket wheel valve stem locations can cause a sensor to not function correctly.
• The sensor activation procedure may have to be repeated up to 3 times before determining a sensor is malfunctioning.
• Occasionally sensors can become mislocated due to previous tire rotations where the sensor learn procedure was not performed. Always learn the sensors to ensure the DTC set is for that actual physical corner of the vehicle. Refer to Tire Pressure Indicator Sensor Learn. Programming and Relearning
• Occasionally sensor transmissions are not received by the RCDLR due to vehicle level RF interference.
Reference Information
Schematic Reference
Tire Pressure Monitoring System Schematics [1][2]Electrical Diagrams
Description and Operation
Tire Pressure Monitor Description and Operation Description and Operation
Electrical Information Reference
• Circuit Testing Circuit Testing
• Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs Wiring Repairs
• Connector Repairs Connector Repairs
Scan Tool Reference
• Scan Tool Data List Scan Tool Data List
• Scan Tool Data Definitions Scan Tool Data Definitions
Circuit/System Testing
1. Ignition OFF, test for less than 2.0 ohms of resistance between the tire pressure module ground circuit terminal 10 and ground.
--> If greater than the specified range, test the ground circuit for an open/high resistance.
2. Ignition ON, verify that a test lamp illuminates between the tire pressure module terminal 1 and ground.
--> If the test lamp does not illuminate, test for an open/high resistance or short to ground in the B+ circuit. If the circuit tests normal, replace the tire pressure module.
3. Ignition OFF, disconnect the harness connector at the affected tire pressure receiver.
4. Ignition OFF, test for less than 2 ohms of resistance between the low reference circuit terminal 3 and ground.
--> If greater than the specified range, test the low reference circuit for an open/high resistance. If circuit tests normal, replace the tire pressure module.
5. Ignition ON, test for 4.75�5.25 volts between the 5 volt reference circuit terminal 1 and ground.
--> If less than the specified range, test the 5 volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the tire pressure module.
--> If greater than the specified range, test the 5 volt reference circuit for a short to voltage. If the circuit tests normal, replace the tire pressure module.
6. Ignition OFF, replace the affected tire pressure receiver with a known good part from one of the other locations.
7. Ignition ON, use the special tool to simulate the tire pressure sensor. Verify the scan tool displays an accurate tire pressure that matches within 27.6 kPa (4 psi) of the special tool simulation display parameters.
--> If the parameters do not match, test the signal circuit for a short to ground, open/high resistance, or short to voltage. If the circuit tests normal, replace the tire pressure module.
8. Using the EL-46079/J-46079 , activate each tire pressure sensor and record each sensors transmission data and physical location. Verify the EL-46079 / J-46079 displays an 8-digit ID number, accurate tire pressure within 27.6 kPa (4 psi), Learn Mode, and at least a 1/4 graph signal strength displayed.
--> If any of the parameters listed above are not displayed, replace the suspect tire pressure sensor.
9. Verify that the tire pressure sensors ID and locations displayed on the scan tool match the ID and location recorded from the special tool.
--> If the ID and location do not match, perform the Tire Pressure Indicator Sensor Learn procedure. Programming and Relearning
10. Test drive the vehicle above 40 km/h (25 mph) for greater than 2 minutes. With the scan tool, observe the suspect Pressure Sensor Mode data parameter. Verify sensor mode changes to Rolling.
--> If the suspect Pressure Sensor Mode does not change, replace the suspect tire pressure sensor.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• Tire Pressure Indicator Sensor Replacement Tire Pressure Sensor Replacement
• Tire Pressure Indicator Receiver Replacement
• Low Tire Pressure Indicator Module Replacement Service and Repair
• Tire Pressure Indicator Sensor Learn Programming and Relearning
• RCDLR replacement Service and Repair
• RCDLR setup, and programming Testing and Inspection