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C0077






C0077-LOW TIRE PRESSURE

For a complete wiring diagram, refer to the Wiring Information Electrical Diagrams.

- When Monitored:
Continuously.

- Set Condition:
A low pressure condition will exist when the tire pressure falls below or is equal to the low pressure threshold value as specified for the vehicle.





1. DTC STATUS

NOTE: If vehicle is equipped with "Light load" reset switch make sure tire pressure matches switch position. Vehicles with a Supplemental Tire Pressure Information Label will have a "Max Load Tire Pressure", and "Light Load Tire Pressure". If the incorrect Placard Values have been programmed, update the Placard Pressures under "Miscellaneous Functions" for the "WCM" and follow the procedure.

NOTE: If the incorrect Placard Values were programmed into the WCM, a DTC could be set. Before continuing with any TPM diagnostic test, using the scan tool, check that the correct Placard Values have been programmed in to the module.

NOTE: If any of the following conditions are present repair them first before continuing with this test.
- Low Tire Pressure DTCs
- Tire Pressure Monitoring (TPM) Sensor Internal fault
- Spare Tire is not equipped with a TPM Sensor and is currently on the vehicle

NOTE: Seasonal temperature changes will affect tire pressure, and may have caused the tire pressure to fall below the low pressure warning threshold. Tire pressure should always be set based on cold inflation tire pressure (placard). This is defined as the tire pressure after a vehicle has not been driven for more then three hours, and in outside ambient temperatures.

1. Correct all tire pressures to the recommended cold inflation tire pressure specifications and wait two minutes for the system to update.
2. Ignition on engine not running.
3. With the scan tool, record and erase DTCs.
4. Test drive the vehicle at speeds greater than 24 km/h (15 mph) for minimum of 10 minutes.
5. With the scan tool, read DTCs.

Is the DTC status at this time?

Yes

- Go To 2

No

- Go To 19

2. LOW TIRE PRESSURE

NOTE: This DTC can be caused by many different factors and might not be a TPM Sensor or a WCM fault. Interference from other elements can over power the sensor/transmitter RF frequency to the WCM making erratic operation to the TPM system. Check the vehicle for aftermarket accessories that could compromise the RF frequency signal before diagnosing the TPM system.

1. Correct all tire pressures to the recommended cold inflation tire pressure specifications and wait two minutes for the system to update.
2. With the scan tool, record and erase DTCs.
3. With the scan tool, read DTCs.

Does the DTC reset or is the status Active for this DTC?

Yes

- Go To 3

No

- Go To 8

3. TIRE PRESSURE MONITORING (TPM) SENSOR

NOTE: The following tests are used to locate the Tire Pressure Monitoring (TPM) Sensor/Transmitter that is setting the low pressure fault. If the tires have been rotated, the Tire Pressure Monitoring (TPM) Sensor/Transmitter is no longer in sequence from the factory. Faults are linked to the sensor/transmitter IDs. You MUST locate the correct Tire Pressure Monitoring (TPM) Sensor/Transmitter that set the fault before.

NOTE: Before continuing with any TPM diagnostic test, using the scan tool and read first set of the Tire Placard Pressure Front and Tire Placard Pressure Rear under Data Display in the WIN. (under the Left Rear Transponder Status) Confirm that the values match the Tire Inflation Pressure (Placard) label located on the Drivers Side B-Pillar. If the incorrect Placard Values have been programmed in the WIN, go to Update Pressure Thresholds under Miscellaneous Functions for the WIN and follow the procedure.If the vehicle is equipped with a WIN Module, go into the Totally Integrated Power Module (TIPM), select Data Display and read "Tire Placard Pressure - Front" and "Tire Placard Pressure - Rear" to confirm the values were programmed correctly. If the Placard values are incorrect in the TIPM, select the Totally Integrated Power Module (TIPM) then under "Miscellaneous" select "Update Pressure Threshold" and enter the placard pressure value as seen on the Tire Inflation Pressure (Placard) label. Repeat step #2 for Diagnostics.

1. With the scan tool, select View Data Display in the WIN and find the compensated tire pressure values located under each of the Sensor Identification locations.

Are any of the compensated tire pressure values are below the Placard Value?

Yes

- Replace the Tire Pressure Monitoring (TPM) Sensor.
- Perform the TPM VERIFICATION TEST. Tire Pressure Monitor (TPM) Verification Test.

No

- Go To 4

4. TPM/RKE ANALYZER

Is there a TPM/RKE Analyzer 9936 available?

Yes

- Go To 5

No

- Go To 7

5. TIRE PRESSURE MONITORING (TPM) SENSOR NON-RESPONSIVE
1. With the TPM-RKE Analyzer 9936, check to see if the any of the TPM Sensors do not respond after repeated attempts or display the following:
- "Damaged Accel"
- "Damaged Temp"
- "Damaged Press"

Are any of the TPM Sensors not responding or displaying the information listed above?

Yes

- Replace the Tire Pressure Monitoring (TPM) Sensor.
- Perform the TPM VERIFICATION TEST. Tire Pressure Monitor (TPM) Verification Test.

No

- Go To 6

6. TPM SENSOR INTERNAL FAULT SET USING TPM/RKE ANALYZER

NOTE: The following procedure is used to locate the TPM Sensor that is setting the sensor internal fault. If the tires have been rotated, the Tire Pressure Monitoring (TPM) Sensor is no longer in sequence from the factory. Faults are linked to the sensor/transmitter IDs. You MUST locate the correct Tire Pressure Monitoring (TPM) Sensor that set the fault before continuing. Use the following method below at every tire location.

NOTE: If the sensor IDs do not match, it may be necessary to move the vehicle to a location away from other TPM sensors and repeat this step.

1. With the scan tool, select Data Display for the WIN.
2. Check to see if the Sensor IDs match what is programmed into the WIN.

Has the Tire Pressure Monitoring (TPM) Sensor been located?

Yes

- Replace the Tire Pressure Monitoring (TPM) Sensor.
- Perform the TPM VERIFICATION TEST. Tire Pressure Monitor (TPM) Verification Test.

No

- Replace the Wireless Control Module (WCM).
- Perform the WCM VERIFICATION TEST. Wireless Control Module (WCM) Verification Test.

7. TIRE PRESSURE MONITORING (TPM) SENSOR INTERNAL FAULT SET

NOTE: Some vehicles will not receive TPM Sensor data when the vehicle is stationary. The vehicle may need to be driven at speeds greater than 15 mph (24 km/h) for about a minute in order to receive TPM Sensor data.

1. Starting with the left front wheel, deflate the tire to 20 PSI, wait two minutes, and check the scan tool for changes to any compensated tire pressure values
2. Look for a tire location whose sensor ID that is not responding.
3. Repeat this test on each wheel on the vehicle until the sensor in question has been identified

Has the Tire Pressure Monitoring (TPM) Sensor been located?

Yes

- Replace the Tire Pressure Monitoring (TPM) Sensor.
- Perform the TPM VERIFICATION TEST. Tire Pressure Monitor (TPM) Verification Test.

No

- Replace the Wireless Control Mode (WCM).
- Perform the WCM VERIFICATION TEST. Wireless Control Module (WCM) Verification Test.

8. LIGHT LOAD RESET SWITCH
1. The Light Load Reset Switch will allow the driver to switch between the max load inflation pressure (cold) low pressure warning threshold and the light load inflation pressure (cold) low pressure warning threshold.

Is this vehicle equipped with a Light Load Reset Switch?

Yes

- Go To 9

No

- Go To 19

9. LIGHT LOAD RESET SWITCH LED LAMP
1. After a WCM ECU Reset, the WCM should be at the Light Load Configuration.

Is the Light Load Reset Switch LED ON?

Yes

- Go To 10

No

- Go To 14

10. LIGHT LOAD RESET SWITCH LED LAMP TEST
1. Press the Light Load Reset Switch.

Did the Light Load Reset Switch LED Turn OFF?

Yes

- Go To 19

No

- Go To 11

11. LIGHT LOAD RESET SWITCH LED CCN TEST
1. With the scan tool, go to "Tire Pressure Load Switch Pressed" under "Miscellaneous Function" in the "CCN - Cabin Control Node".
2. Start the actuation by pressing the "SET" button.

Did the Light Load Reset Switch LED Turn OFF?

Yes

- Stop the actuation.
- Replace the Light Load Reset Switch.
- Perform the TPM VERIFICATION TEST. Tire Pressure Monitor (TPM) Verification Test.

No

- Stop the actuation.
- Go To 12

12. LIGHT LOAD RESET SWITCH LED CCN TEST
1. With the scan tool, go to "Tire Pressure Load Switch Pressed" under "Miscellaneous Function" in the "CCN - Cabin Control Node".
2. Start the actuation. On the next screen pick "False"

Did the Light Load Reset Switch LED Turn OFF?

Yes

- Stop the actuation.
- Replace the Wireless Control Mode (WCM).
- Perform the WCM VERIFICATION TEST. Wireless Control Module (WCM) Verification Test.

No

- Stop the actuation.
- Repair the Short to voltage on the LED circuit.
- Go To 13

13. SHORT TO GROUND ON LIGHT LOAD SWITCH LED CIRCUIT




1. Turn ignition off to the lock position.
2. Disconnect the TPM Switch harness connector.
3. Disconnect the CCN C1 harness connector.
4. Measure the resistance of the (G561) TPM Indicator Control circuit at the TPM Switch harness connector to ground.

Was there a short to ground?

Yes

- Repair (G561) TPM Indicator Control circuit for a short to ground.
- Perform the TPM VERIFICATION TEST. Tire Pressure Monitor (TPM) Verification Test.

No

- Replace the Cabin Control Node (CCN).
- Perform the BODY VERIFICATION TEST. Body Verification Test.

14. LIGHT LOAD RESET SWITCH LED CCN TEST
1. Go To "Tire Pressure Load Switch Indicator" under "Miscellaneous Function" in the "CCN - Cabin Control Node".
2. Start the actuation by pressing the "True" button.

Did the Light Load Reset Switch LED Turn ON?

Yes

- Stop the actuation.
- Go To 4

No

- Stop the actuation.
- Go To 15

15. WCM / LIGHT LOAD SWITCH / WIRING TO LED CIRCUIT




1. Turn the ignition off to the lock position.
2. Disconnect the TPM Switch harness connector.
3. Disconnect the CCN C1.
4. Measure the resistance of the (G561) circuit between the TPM Switch harness connector and the CCN harness connector.

Is the resistance below 5 Ohms?

Yes

- Go To 16

No

- Repair (G561) TPM Indicator Control circuit for an open.
- Perform the TPM VERIFICATION TEST. Tire Pressure Monitor (TPM) Verification Test.

16. F504 FUSED IGNITION SWITCH OUTPUT RUN CIRCUIT




1. Ignition on, engine not running.
2. Using a 12-volt test light connected to ground, check the (F504) Fused Ignition Switch Output Run circuit.

Does the test light illuminate brightly?

Yes

- Go To 17

No

- Repair the (F504) Fused Ignition Switch Output Run circuit for an open.
- Perform the TPM VERIFICATION TEST. Tire Pressure Monitor (TPM) Verification Test.

17. LIGHT LOAD RESET SWITCH




1. Turn the ignition off to the lock position.
2. Connect the Light Load Reset Switch harness connector.
3. Connect a jumper wire between (G561) TPM Indicator Control circuit and ground in the CCN C1 harness connector.
4. Ignition on, engine not running.

Does the Light Load Reset Switch LED turn on?

Yes

- Go To 18

No

- Replace the Light load Reset Switch.
- Perform the TPM VERIFICATION TEST. Tire Pressure Monitor (TPM) Verification Test.

18. LIGHT LOAD RESET SWITCH LED CCN TEST
1. Go To "Tire Pressure Load Switch indicator" under "Miscellaneous Function" in the "CCN - Cabin Control Node".
2. Start the actuation. On the next screen press the "true" button.

Did the Light Load Reset Switch LED Turn ON?

Yes

- Stop the actuation.
- Replace the Wireless Control Module (WCM).
- Perform WCM VERIFICATION TEST. Wireless Control Module (WCM) Verification Test.

No

- Stop the actuation.
- Replace the Cabin Control Node (CCN).
- Perform the BODY VERIFICATION TEST. Body Verification Test.

19. INTERMITTENT TIRE PRESSURE MONITORING (TPM) SENSOR DTC
1. The conditions necessary to set this DTC are not present at this time.
2. Perform any Technical Service Bulletins that may apply to this condition.
3. With the scan tool, erase DTCs.
4. Test drive the vehicle for a minimum of 10 minutes with vehicle speed greater than 24 km/h (15 mph).
5. With the scan tool, read DTCs.

Does the DTC reset or is the status Active for this DTC?

Yes

- Repair as necessary.
- Perform the TPM VERIFICATION TEST. Tire Pressure Monitor (TPM) Verification Test.

No

- Test complete.

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