DTC C0227 or C027 LF Wheel Speed Signal Erratic. GMC Truck Savana 2000

For 1990-2009 cars only

Makes 🢒 GMC_Truck 🢒 2000 🢒 Savana 🢒 DTC 🢒 DTC C0227 or C027 LF Wheel Speed Signal Erratic

Circuit Description

As the wheel spins, the wheel speed sensor produces an AC signal. The electronic brake control module (EBCM) uses the frequency of the AC signal to calculate the wheel speed.

Conditions for Running the DTC

•	Ignition switch in the RUN position.

•	All wheel speed sensor signals are greater than 32 km/h (20 mph) with brake applied or 19 km/h (12 mph) with brake released.

Conditions for Setting the DTC

Either of the following conditions will set DTC C0227.

•	A sudden loss of the corresponding front wheel speed sensor signal is detected for 15 milliseconds.

•	A sudden increase is detected in the corresponding front wheel speed sensor signal at a rate greater than 8.8 km/h (5.5 mph) for 105 milliseconds.

Action Taken When the DTC Sets

•	The ABS indicator lamp turns on.

•	The ABS is disabled for as long as the malfunction is present. If the malfunction occurs three or more separate times, the ABS will be disabled for the remainder of the ignition cycle.

Conditions for Clearing the DTC

•	Repair the condition(s) 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. Refer to Testing for Intermittent Conditions and Poor Connections , Wiring Repairs , and Connector Repairs in Wiring Systems.

Step	Action	Value(s)	Yes	No
Schematic References: 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 of a speed greater than the specified value. Does the DTC set?	13 km/h (8 mph)	Go to Step 3	Go to Diagnostic Aids
3	Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information. Disconnect the wheel speed sensor connector. Use a DMM in order to measure the resistance across the wheel speed sensor. Does the resistance measure within the specified range?	1575-3850 ohms	Go to Step 4	Go to Step 8
4	Spin the wheel by hand as fast as possible. Use a DMM in order to measure the AC voltage generated by the wheel speed sensor. Does the AC voltage measure greater than the specified value?	50 mV	Go to Step 5	Go to Step 8
5	Inspect for poor connections at the harness connector of the wheel speed sensor. 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 10	Go to Step 6
6	Test the wheel speed sensor circuits for the following: An open A short to ground A short to voltage Shorted together Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition?	--	Go to Step 10	Go to Step 7
7	Inspect for poor connections at the harness connector for 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 10	Go to Step 9
8	Replace the wheel speed sensor. Refer to Wheel Speed Sensor Replacement . Did you complete the replacement?	--	Go to Step 10	--
9	Important: Perform the tire size calibration in Scan Tool Diagnostics. Replace the EBCM. Refer to Electronic Brake Control Module Replacement . Did you complete the replacement?	--	Go to Step 10	--
10	Use the scan tool in order to clear the DTCs. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text. Does the DTC reset?	--	Go to Step 2	System OK