DTC C1276 Delivered Torque Signal Circuit Malfunction. Buick Century (China) (CNG) 1999

For 1990-2009 cars only

Makes 🢒 Buick 🢒 1999 🢒 Century (China) (CNG) 🢒 Brakes 🢒 Antilock Brake System 🢒 DTC C1276 Delivered Torque Signal Circuit Malfunction

ABS Components
Antilock Brake System Schematics
Handling Electrostatic Discharge Sensitive Parts Notice
Handling Electrostatic Discharge Sensitive Parts Notice

Circuit Description

Traction Control is simultaneously controlled by the EBTCM and the Powertrain Control Module (PCM). The PCM sends a DELIVERED TORQUE message via a Pulse Width Modulated (PWM) signal to the EBTCM confirming the delivered torque level for proper Traction Control system operation. The EBTCM supplies the pull up voltage.

Conditions for Setting the DTC

DTC C1276 can be set anytime when ignition voltage is present. A malfunction exists if the PWM signal is out of range or no signal is received for a period of 7 seconds.

Action Taken When the DTC Sets

•	A malfunction DTC is stored.

•	TCS is disabled.

•	Traction Control (TRAC OFF) indicator is turned on.

•	Service Vehicle Soon Indicator is turned on.

•	ABS remains functional.

Conditions for Clearing the DTC

•	Condition for DTC is no longer present and scan tool clear DTC function is used.

•	100 ignition cycles have passed with no DTCs detected.

Diagnostic Aids

•	Possible causes for DTC C1276 to set are:

-	Delivered Torque line (CKT464) open.

-	Delivered Torque line (CKT464) shorted to ground.

-	Delivered Torque line (CKT464) shorted to voltage.

-	Communication frequency malfunction.

•	It is very important that a thorough inspection of the wiring and connectors be performed. Failure to carefully and fully inspect wiring and connectors may result in misdiagnosis, causing part replacement with reappearance of the malfunction.

•	If an intermittent malfunction exists refer to Intermittents and Poor Connections Diagnosis in Wiring Systems.

Step	Action	Value(s)	Yes	No
1	Was the Diagnostic System Check performed?	--	Go to Step 2	Go to Diagnostic System Check - ABS
2	Turn the ignition switch to the OFF position. Disconnect the EBTCM connector. Install the J 39700 Universal Pinout Box using the J 39700-99 Cable Adapter to the EBTCM harness connector only. Disconnect the PCM connector C2. Using a DMM, measure the resistance between terminal C1 of Universal Pinout Box and the PCM connector C2 terminal 9. Is the resistance within the range specified in the Value(s) column?	0-2 ohms	Go to Step 4	Go to Step 3
3	Repair CKT 464 for an open or high resistance. Refer to Wiring Repairs in Wiring Systems. Is the repair complete?	--	Go to Diagnostic System Check - ABS	--
4	Connect the DMM between terminals C1 and D of the Universal Pinout Box. Measure CKT 464 for continuity to ground. Is CKT 464 shorted to ground?	--	Go to Step 5	Go to Step 6
5	Repair CKT 464 for a short to ground. Refer to Wiring Repairs in Wiring Systems. Is the repair complete?	--	Go to Diagnostic System Check - ABS	--
6	DMM still connected between terminals C1 and D of the Universal Pinout Box. Turn the ignition switch to the ON position, engine off. Measure CKT 464 for voltage between terminals C1 and D of Universal Pinout Box. Is any voltage present on CKT 464 with the ignition ON?	--	Go to Step 7	Go to Step 8
7	Repair CKT 464 for a short to voltage. Refer to Wiring Repairs in Wiring Systems. Is the repair complete?	--	Go to Diagnostic System Check - ABS	--
8	Turn the ignition switch to the OFF position. Connect the EBTCM to the Universal Pinout Box using the J 39700-99 Cable Adapter. Start the engine. Using a DMM, measure the voltage between terminals C1 and D of Universal Pinout box. Is the voltage within the range specified in the Value(s) column?	4.5-5.5 V	Go to Step 10	Go to Step 9
9	Replace the EBTCM. Refer to Electronic Brake Control Module/Electronic Brake and Track Control Module Replacement . Is the replacement complete?	--	Go to Diagnostic System Check - ABS	--
10	Suspect the PCM. Refer to A Powertrain On Board Diagnostic (OBD) System Check or A Powertrain On Board Diagnostic (OBD) System Check in Engine Controls. Is the diagnosis complete?	--	Go to Diagnostic System Check - ABS	--