C1245
DTC C1245
Circuit Description
The Tire Pressure Monitor (TPM) system uses the Electronic Brake Control Module (EBCM), and the Antilock Brake System (ABS) wheel speed sensor inputs to monitor tire pressure. The EBCM contains software to calculate relative tire pressure differences.
The EBCM monitors the ABS wheel speed sensor inputs, which will all be the same as the learned calibration if the tire pressures stay the same. If the pressure increases or decreases in one tire so to will that tire's circumference and radius, which causes that wheel speed sensor input to change. The EBCM recognizes this change in wheel speed as a tire pressure condition.
Conditions for Running the DTC
^ No ABS or TCS malfunctions present.
^ The calibration process is complete.
^ The vehicle speed is between 24 - 145 km/h (15 - 90 mph).
Conditions for Setting the DTC
^ The EBCM detects a tire pressure difference in one tire of 69 kPa (10 psi) higher or lower than the other three.
^ A loss of, or low system battery voltage.
Actions Taken When the DTC Sets
^ A DTC C1245 is set in memory.
^ The IPC displays the LOW TIRE PRESSURE warning indicator.
^ The TPM system is disabled.
Conditions for Clearing the DTC
^ A current DTC will clear with no malfunction present and the calibration process is complete.
^ A history DTC will clear after 100 consecutive ignition cycles with no malfunction present and the calibration process is complete.
^ Using the scan tool
Diagnostic Aids
Any of the following conditions can also cause this DTC to set.
^ The tire pressures have been altered without calibrating the TPM system.
^ The tires have been rotated or changed without calibrating the TPM system.
^ The tires are different in size than the original equipment manufacturer's.
^ Rough or slippery road conditions, i.e. dirt, gravel, wet, snow, or ice
^ Tires out of balance
^ A suspension out of alignment
Test Description
The number below refers to the step number on the diagnostic table.
5. This step inspects the tires for proper tire pressures.