P1669

Wiring Diagram:

ABS Unit Expected:

P1669- ABS UNIT EXPECTED
The electronic brake and traction control module (EBTCM) sends torque reduction request information to the ECM over circuit 463. This information is needed by the ECM to reduce engine power via spark retard or injector disable (in extreme cases) during a traction control event The torque reduction request signal is a 0 to 12 volt pulse width modulated square wave created by the EBTCM grounding circuit 463. The signal circuit is pulled up to 9-12 volts in both the ECM and EBTCM. The EBTCM continuously pulse width modules the signal over circuit 463 even if no traction control event is present. This is to allow the ECM to detect a fault in the torque reduction request circuit. DTC P1669 will set if the ECM does not receive a signal from the EBTCM over the torque reduction request circuit with the engine running when the ECM has the antilock brake option programmed.

DTC PARAMETERS
DTC P1669 will set if the ECM does not receive any torque reduction request signal over circuit 463 when:
^ Condition exists for longer than 2 seconds
^ ECM has ABS programmed as an option
^ Engine speed is greater than 600 rpm

DTC P1669 runs continuously with engine running. P1669 is a type D DTC

DIAGNOSTIC AIDS

IMPORTANT: If this DTC is set on a non-ABS vehicle. the ECM option content was programmed incorrectly. If this is the case, reprogram the ECM without ABS.

To locate an intermittent problem, use Scan tool to monitor DTC P1669 LAST TEST with engine running. Wiggling wires while watching for a change from PASSED to FAILED may locate the area where an open, short to ground or short to voltage on circuit 463 exists.

NOTE: If a fault exists on circuit 463. the EBTCM will NOT set a DTC.