DTC C0236 or C036 Rear Wheel Speed Signal Circuit Missing. GMC Truck Savana 2000

For 1990-2009 cars only

Makes 🢒 GMC_Truck 🢒 2000 🢒 Savana 🢒 DTC 🢒 DTC C0236 or C036 Rear Wheel Speed Signal Circuit Missing

Circuit Description

The EBCM receives the rear wheel speed signal from the VCM/PCM. The signal from the VCM/PCM is always high (12 Volts) when the ignition is on and the vehicle is not moving. When the vehicle is moving, the VCM/PCM toggles this voltage on and off. The EBCM uses the frequency of this signal to calculate the rear wheel speed.

Conditions for Running the DTC

•	The ignition is ON.

•	The front wheel speed sensor signals are both greater than 13 km/h (8 mph).

Conditions for Setting the DTC

The rear wheel speed sensor signal is less than 6 km/h (4 mph) for 5 seconds.

Action Taken When the DTC Sets

•	The ABS and BRAKE indicators are commanded on.

•	The ABS is disabled for as long as the malfunction is present.

Conditions for Clearing the DTC

•	Repair the conditions responsible for setting the DTC.

•	Use a scan tool in order to clear the DTC.

Diagnostic Aids

Thoroughly inspect connections or circuitry that may cause an intermittent malfunction. Inspect for the following:

•	Backed out terminals

•	Improper mating

•	Broken locks

•

Corrosion

•	Improperly formed or damaged terminals

•	Poor terminal-to-wiring connections

•	Physically damaged wiring

•	Wiring broken inside the insulation

Test Description

The number below refers to the step number on the diagnostic table.

This step tests if the VCM/PCM is sending a vehicle speed signal to the EBCM. The voltage should measure approximately 50% of battery voltage while the driveshaft is rotating.

Step	Action	Value(s)	Yes	No
Schematic Reference: Antilock Brake System Schematics
1	Did you perform the ABS Diagnostic System Check?	--	Go to Step 2	Go to Diagnostic System Check
2	Use a scan tool in order to clear the DTC(s). Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text. Does the DTC set?	--	Go to Step 3	Go to Diagnostic Aids
3	Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information. Turn the ignition OFF. Disconnect connector C1 from the EBCM. Connect a DMM between the vehicle speed signal circuit (at connector C1) and a good ground. Set up the DMM to measure DC voltage. Place the transmission shift lever in neutral. Turn the igniton ON. Spin the rear wheels as fast as is possible by hand and while ensuring that the driveshaft is rotating, observe the DMM. Does the voltage measure within the specified value?	5-7 V	Go to Step 5	Go to Step 4
4	Test the vehicle speed signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	--	Go to Step 9	Go to Step 7
5	Inspect for poor connections at the harness connector of the EBCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?	--	Go to Step 9	Go to Step 6
6	Important: Perform the Tire Size Calibration procedure. Replace the EBCM. Refer to Electronic Brake Control Module Replacement . Did you complete the replacement?	--	Go to Step 9	--
7	Inspect for poor connections at the harness connector of the VCM/PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition?	--	Go to Step 9	Go to Step 8
8	Important: Perform the setup procedure for the VCM/PCM. Replace the VCM/PCM. Refer to VCM Replacement/Programming in Engine Controls-4.3L, VCM Replacement/Programming in Engine Controls - 5.0 - 5.7, Powertrain Control Module Replacement/Programming in Engine Controls - 6.5, or VCM Replacement/Programming in Engine Controls - 7.4. Did you complete the replacement?	--	Go to Step 9	--
9	Use the scan tool in order to clear the DTC. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text. Does the DTC set?	--	Go to Step 3	System OK