Circuit Description
The tire pressure monitor (TPM) system has a radio frequency transmitting pressure sensor in each wheel/tire assembly. As vehicle speed increases above 32 km/h (20 mph) the sensor internal roll switch closes which puts the sensors into drive mode. In this mode, the sensors transmit once every 60 seconds to the remote control door lock receiver (RCDLR). The data within the sensors radio frequency transmission is translated by the RCDLR into sensor presence, sensor mode, and tire pressure. The RCDLR waits for the first sensor to go into drive mode then checks if all sensors are in drive mode.
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 above 32 km/h (20 mph).
Conditions for Setting the DTC
Any given sensor does not go into drive mode, or does not transmit at all for 15 minutes.
Action Taken When the DTC Sets
| • | A DTC is stored in memory. |
| • | The driver information center (DIC) displays the SERVICE TPM SYSTEM message. |
| • | The DIC displays the suspect tire pressure as dashes. |
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. |
Diagnostic Aids
| • | Some aftermarket wheel valve stem holes are located further from the wheel rim than the original equipment wheels. When using the J-46079 tire pressure monitor (TPM) diagnostic tool to activate a sensor, ensure the tool 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 not transmitting. |
| • | Occasionally, sensors can become mislocated due to previous tire rotations where the sensor learn procedure was not performed. Always learn the current sensor locations to ensure the DTC set is for that actual physical corner of the vehicle. Refer to Tire Pressure Sensor Learn . |
| • | If the vehicle is stationary for more than 15 minutes after being driven, the sensors will go into stationary mode. Always test drive the vehicle above 32 km/h (20 mph) to ensure the sensors are in drive mode before viewing tire pressures on the DIC. |
| • | If there is an open in the serial data circuit to the receiver, the DIC will display dashes for all tire pressures and the SERVICE TPM SYSTEM message. |
| • | Loss of, or low system battery voltage will cause all of the sensor ID codes to be erased from the RCDLR memory and set all 4 sensor DTCs. If this condition is suspected, refer to Tire Pressure Sensor Learn . |
| • | Occasionally, sensor transmission will not be received by the RCDLR due to vehicle level radio frequency interference. |
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
This step tests if the sensors can transmit valid data with good signal strength in response to low frequency activation. During this step it is important to observe the signal strength graph on the TPM tool display screen. Any more that 1/4 graph displayed can be considered good signal strength.
-
This step tests if any sensors are mislocated.
-
This step tests if the RCDLR can receive, learn, and translate the data contained in simulated sensor transmissions.
-
This step tests if the sensors 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 - Vehicle? | -- | Go to Step 2 | |
Using the J-46079 Tire Pressure Monitor (TPM) Diagnostic Tool, activate each tire pressure sensor and record each sensor's transmission data and physical location on the repair order. Does the TPM diagnostic tool display each sensor's transmission data as specified? | 8-digit ID number, accurate tire pressure +/- 1 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 physical 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 as specified? | 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/RF Tire Pressure -30 psi, LR Pressure Sensor ID-123404/LR Tire Pressure -40 psi +/- 4 psi | Go to Step 5 | Go to Step 8 | |
5 | Learn the tire pressure sensors. Refer to Tire Pressure Sensor Learn . Did you complete the procedure? | -- | Go to Step 6 | -- |
Does the DTC reset? | -- | Go to Step 7 | System OK | |
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 RCDLR. Refer to Remote Control Door Lock Receiver Replacement . Did you complete the replacement? | -- | Go to Step 9 | -- |
9 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
