C0077 Jeep OBD Code Diagnostic Procedure

C0077 Jeep OBD Code

LOW TIRE PRESSURE

For a complete wiring diagram Refer to Section 8W.

Theory of Operation

The Tire Pressure Monitoring System (TPMS) will warn the driver of a low tire pressure based on the vehicle recommended cold placard pressure. The tire pressure will vary with temperature by
about 1 psi (6.9 kPa) for every 12 (6.5). This means that when the outside temperature decreases, the tire pressure will decrease. Tire pressure should always be set based on cold inflation
tire pressure. This is defined as the tire pressure after a vehicle has not been driven for more than 3 hours – and in outside ambient temperature. . The tire pressure will also increase as the vehicle
is driven – this is normal and there should be no adjustment for this increased pressure. The TPM System will warn the driver of a low tire pressure if the tire pressure falls below the low pressure warning
threshold for any reason, including low temperature effects. The TPM System will continue to warn the driver of low tire pressure as long as the condition exists, and will not turn off until the tire pressure
is at or above recommended cold placard pressure. Once the low tire pressure warning has been illuminated, the tire pressure must be increased to the recommended cold placard pressure in order for the TPM
warning lamp to be turned off. The system will automatically update and the TPM warning lamp will extinguish once the updated tire pressures have been received. The vehicle may need to be driven for up
to 10 minutes above 15 mph (25 kph) to receive this information. Seasonal temperature changes will affect tire pressure, and the TPM system will monitor the actual tire pressure in the tire. For example,
your vehicle may have a recommended cold (parked for more than 3 hours) placard of 30 (207 kPa). If the ambient temperature is 68 (20) and the measured tire pressure is 27 psi (186 kPa), a
temperature drop to 20 (-7) will decrease the tire pressure to approximately 23 psi (157 kPa). This tire pressure is sufficiently low enough to turn ON the TPM lamp. Driving the vehicle may
cause the tire pressure to rise to approximately 27 psi (186 kPa), but the TPM lamp will still be ON. In this situation, the TPM lamp will turn OFF only after the tires have been inflated to the vehicle
recommended cold placard pressure value.

  • 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.
Possible Causes
INTERMITTENT PERFORMANCE DTC
INCORRECT PLACARD VALUES
INCORRECT TIRE PRESSURE
TIRE PRESSURE SENSOR
WCM (SKREEM)

Diagnostic Test

1. DTC STATUS IS ACTIVE

NOTE:
If the incorrect Placard Values were programmed into the WCM/SKREEM, 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 the following conditions are present:
  • Low Tire Pressure DTC (C0077) (Active)
  • Spare Tire is not equipped with a Tire Pressure Sensor
  • Spare Tire is currently on the vehicle
  • Repair the tire and place it back on the vehicle.
  • Test drive the vehicle.
  • If the DTC(s) reset continue with the diagnostic procedure.
  • Turn the ignition on.
  • With the scan tool, select View DTCs in the Wireless Control Module (SKREEM).

Is the DTC status Active at this time?

Yes

  • Go to  2

No

  • Go to  5


2. INCORRECT PLACARD VALUES

With the scan tool read the placard values programed in the WCM

Does the programed placard values equal the placard value on the vehicle?

Yes

  • Go to  3

No

  • Update placard pressure values in the WCM.

 

  • Perform TPM VERIFICATION TEST.(Refer to 22 – TIRES/WHEELS/TIRE PRESSURE MONITORING – STANDARD PROCEDURE)

 


3. LOW TIRE PRESSURE

With the scan tool, clear DTCs in the Wireless Control Module (SKREEM).

With the scan tool, view tire pressure values.

Are all tire pressure values at or exceed placard values?

Yes

  • Go to  4

No

  • Fill all tires to placard pressure specifications.

 

  • Perform TPM VERIFICATION TEST.(Refer to 22 – TIRES/WHEELS/TIRE PRESSURE MONITORING – STANDARD PROCEDURE)

 


4. TIRE PRESSURE SENSOR

NOTE:
Before continuing, ensure the tire is free from any leaks or damage that would cause a low tire pressure condition. If a problem is found, repair as necessary and retest.

  • Turn the ignition off.
  • Replace the Tire Pressure Sensor in accordance with the Service Information.
  • With the scan tool, clear DTCs in the Wireless Control Module (SKREEM).
  • Test Drive the vehicle for a minimum of 10 minutes with vehicle speed greater than 15 MPH (24 km/h).
  • With the scan tool, select View DTCs in the Wireless Control Module (SKREEM).

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

Yes

  • Replace the Wireless Control Module (SKREEM) in accordance with the Service Information.

 

  • Perform TPM VERIFICATION TEST.(Refer to 22 – TIRES/WHEELS – DIAGNOSIS AND TESTING)

 

No

  • Test Complete.
  • Perform TPM VERIFICATION TEST.(Refer to 22 – TIRES/WHEELS/TIRE PRESSURE MONITORING – STANDARD PROCEDURE)


5. INTERMITTENT TIRE PRESSURE SENSOR DTC

  • The conditions necessary to set this DTC are not present at this time.
  • Refer to any Technical Service Bulletins that may apply to this condition.
  • With the scan tool, clear DTCs in the Wireless Control Module (SKREEM).
  • Test Drive the vehicle for a minimum of 10 minutes with vehicle speed greater than 15 MPH (24 km/h).
  • With the scan tool, select View DTCs in the Wireless Control Module (SKREEM).

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

Yes

  • Repair as necessary.
  • Perform TPM VERIFICATION TEST.(Refer to 22 – TIRES/WHEELS – DIAGNOSIS AND TESTING)

No

  • Test complete.
  • Perform TPM VERIFICATION TEST.(Refer to 22 – TIRES/WHEELS/TIRE PRESSURE MONITORING – STANDARD PROCEDURE)
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