Circuit Description
The tire pressure monitor (TPM) system has 4 radio frequency (RF) transmitting pressure sensors inside each wheel/tire assembly. As vehicle speed increases to at least 32 km/h (20 mph) the sensor's internal roll switch closes which puts the sensors into drive mode. The sensors begin to transmit once every 60 seconds to the passenger door module (PDM). The data within the sensors RF transmission is translated by the PDM into sensor presence, sensor mode, and tire pressure. If a sensor did not go into drive mode, or is not transmitting at all, the PDM will set the appropriate DTC.
DTC Descriptors
This diagnostic procedure supports the following DTCs:
| • | 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 |
Conditions for Running the DTC
Vehicle speed is 40 km/h (25 mph), or greater for 2 minutes.
Conditions for Setting the DTC
Any given sensor stops transmitting for 5 minutes.
Action Taken When the DTC Sets
| • | A DTC is stored in memory. |
| • | The driver information center (DIC) displays the SERVICE TIRE MONITOR warning message. |
Conditions for Clearing the DTC
| • | A current DTC will clear when the malfunction is no longer present. |
| • | A history DTC will clear after 100 consecutive malfunction free ignition cycles. |
| • | Using a scan tool |
Diagnostic Aids
| • | 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 Sensor Learn . |
| • | Some aftermarket wheel valve stem holes are located further form the wheel rim than the original equipment wheels. When using the J-46079 to activate a sensor, ensure the tool's antenna is no further than 6 inches from the sensor. |
| • | The sensor activation procedure may have to be repeated up to 3 times before determining a sensor is malfunctioning. |
| • | Occasionally sensor transmissions are not received by the PDM due to vehicle level RF interference. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
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This step tests if the sensors can transmit valid data with good signal strength in response to a low frequency activation. During this step it is important to observe the signal strength graph on the TPM tool's display screen. Any more that 1/4 graph displayed can be considered good signal strength.
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This step tests if any sensors are mislocated.
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This step tests if the PDM can receive, learn and translate data contained in simulated sensor transmissions.
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This step tests if the sensor's internal roll switch is functioning properly.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Tire Pressure Monitoring System Schematics | ||||
1 | Did you perform the Diagnostic System Check - Tire Pressure Monitoring? | -- | Go to Step 2 | |
Using the J-46079 Tire Pressure Monitor Diagnostic Tool, activate each tire pressure sensor and record each sensor's transmission data and physical location on the repair order. Does the J-46079 display each sensor's transmission data as specified? | 8 digit ID number, accurate tire pressure +/- 2 psi, Learn Mode, good signal strength | Go to Step 3 | Go to Step 7 | |
Do the Ids and their locations observed on the scan tool match the IDs and locations recorded on the repair order? | -- | Go to Step 4 | Go to Step 5 | |
Does the scan tool display all 4 sensor locations, IDs, and tire pressures? | LF Pressure Sensor ID-123401/LF Tire Pressure-10 psi, RF Pressure Sensor ID-123402/RF Tire Pressure-20 psi, RR Pressure Sensor ID-123403/RR Tire Pressure-30 psi, LR Pressure Sensor ID-123404/LR Tire Presure-40 psi +/- 4psi | Go to Step 5 | Go to Step 8 | |
5 | Learn the tire pressure sensors. Refer to Tire Pressure Sensor Learn . Did you complete the learn procedure? | -- | Go to Step 6 | -- |
Does the scan tool indicate that the suspect Pressure Sensor Mode changes from Wake to Drive? | -- | System OK | Go to Step 7 | |
7 | Replace the suspect tire pressure sensor. Refer to Tire Pressure Indicator Sensor Replacement . Did you complete the replacement? | -- | Go to Step 9 | -- |
8 | Replace the PDM/window switch assembly. Refer to Door Lock and Side Window Switch Replacement - Passenger Side in Doors. Did you complete the replacement? | -- | Go to Step 9 | -- |
9 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
