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JOHN aka Eauto
JOHN aka Eauto, The Car Guy
Category: Chevy
Satisfied Customers: 15038
Experience:  ase tech
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I have 2001 silverado 3500 4x4 replaced abs module and pump

Customer Question

i have 2001 silverado 3500 4x4 replaced abs module and pump assembly with new oe light went off, test drive as i came back in light popped on scanner says speed sensor miss match all tires are new /same size correct air psi rear tires ( by scanner says they are 10 mph faster new
JA: Is there a code associated with the error? Have you checked the ABS fluid?
Customer: co238,yes
JA: What is the model of your '01 Chevy?
Customer: silverado 35004x4
JA: Are you hoping to fix this yourself? What have you tried so far?
Customer: checking air looked for loose wires etc
JA: Anything else you think the mechanic should know?
Customer: was not doing this until abs pump went out
JA: Got it. I'm sending you to a secure page where you can book your 1:1 with the Chevy Mechanic. I'll share everything we've discussed.
Submitted: 4 months ago.
Category: Chevy
Expert:  JOHN aka Eauto replied 4 months ago.

did you have the module programmed?

Customer: replied 4 months ago.
Customer: replied 4 months ago.
Can i do that with may scanner
Expert:  JOHN aka Eauto replied 4 months ago.

whats your scanner?

Expert:  JOHN aka Eauto replied 4 months ago.

As the front wheels spin, the wheel speed sensors (WSS's) produce an AC signal. The electronic brake control module (EBCM) uses the frequency of the AC signal to calculate the wheel speed. The powertrain control module (PCM) converts the data from the vehicle speed sensor (VSS) to a 128k pulses/mile signal. The EBCM uses the vehicle speed signal from the PCM in order to calculate the rear wheel speed.

The ignition is ON and the vehicle speed is between 24 km/h (15 mph) and 80 km/h (50 mph).

The EBCM detects that one wheel speed input is 10 percent greater than or 10 percent less than the other wheel speed inputs within 3.2 km (2 mi) of driving.

If equipped, the following actions occur:

->The EBCM disables the ABS/TCS/DRP.

->The ABS indicator turns ON.

->The TRACTION OFF indicator turns ON.

->The red brake warning indicator turns ON.

The conditions for setting the DTC are no longer present and you use the scan tool Clear DTCs function.

Installing one tire of significantly different size on the vehicle causes DTC C0238 to set. Operating the vehicle with a tire that has very low air pressure may also set this DTC. Inspect the vehicle for an incorrect or damaged wheel speed sensor or vehicle speed sensor if the tires and the EBCM and PCM calibrations are OK.

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

  1. If the front tires are not the same size as the rear tires, the EBCM calibration must match the FRONT tire size and the PCM calibration must match the REAR tire size.