C1298

EBCM/Accelerometer Schematic:

CIRCUIT DESCRIPTION
The Electronic Brake Control Module (EBCM) provides power (5 volts) and ground to the accelerometer through CKT 9Q01 and CKT 9R01 respectively. The accelerometer converts the change in vehicle motion, or inertia, into a voltage signal. This signal is sent to the EBCM through CKT 9S01.

The Accelerometer - provides additional vehicle speed reference to the EBCM. The voltage signal ranges, from 2.4 to 2.6 volts at zero speed change (constant motion). The accelerometer voltage signal drops when the vehicle is under acceleration. The accelerometer voltage signal increases when the vehicle is under deceleration.

CONDITIONS FOR SETTING THE DTC
This Diagnostic Trouble Code (DTC) will set when the following conditions are met:
^ This DTC can be set anytime after initialization is completed.
^ The EBCM detects an open, or short to battery, in the accelerometer signal circuit (CKT 9S01).

ACTION TAKEN WHEN THE DTC SETS
A malfunction DTC is stored, ABS is disabled and the ABS indicator is turned ON. If failure occurs during an ABS event, ABS is disabled after the completion of the ABS event.

CONDITIONS FOR CLEARING THE DTC
^ Conditions for the malfunction are no longer present and the Tech 2 scan tool Clear DTC Information function is used.
^ One hundred drive cycles have passed with no malfunctions detected.

DIAGNOSTIC AIDS
The frequency of the malfunction can be checked by using the Enhanced Diagnostic function of the Tech 2 scan tool, as described in Enhanced Diagnostics.

An Intermittent Malfunction - may be caused by a poor connection, rubbed through wire insulation or a wire that is broken inside the insulation.

Any Circuitry That Is Suspected - of causing the intermittent complaint should be thoroughly checked for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wiring connections or physical damage to the wiring harness.

DTC C1298 Accelerometer Circuit Open Or Shorted To Voltage (Part 1 Of 2):

DTC C1298 Accelerometer Circuit Open Or Shorted To Voltage (Part 2 Of 2):

TEST DESCRIPTION
The numbers below refer to step numbers on the diagnostic table.
[2] Verifies whether the malfunction is currently present.
[3] Checks for a short to voltage in the accelerometer signal circuit.
[4] Checks for high resistance in the accelerometer signal circuit.
[5] Checks for a possible intermittent malfunction due to poor terminal contact.
[6] Checks for a malfunction in either the accelerometer or EBCM.