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C0237, C0227, C0238, C0267 Codes: ABS and Brake Light On in 2002 Chevy S10 4.3L ZR2 with 123,000 Miles

Model: Unknown Fault Code: C0227 Posted: 2014-09-29 11:29

Hi everyone, I'm looking for help diagnosing an issue on my 2002 Chevrolet S10 4.3L ZR2 (automatic transmission) with 123,000 miles. The ABS and brake warning lights come on intermittently. I've already tried replacing the ABS control module and repaired a few suspected cracked wiring joints based on forum advice. I took it to AutoZone and retrieved the following diagnostic codes: - C0237: Rear Wheel Speed Signal Circuit Erratic - C0227: Left Front Wheel Speed Signal Erratic - C0238: Wheel Speed Mismatch - C0267: Pump Motor Circuit Open I'm having trouble finding clear explanations for these specific codes online. Can anyone provide insight into what each code means and how to troubleshoot them? In particular, I'm wondering if tire imbalance or mismatch could be contributing—especially since the previous owner recently replaced ball joints and had worn tires that weren't perfectly even. I've just installed new 31x10.50 tires with proper alignment (all within specification), so I suspect this might have triggered a sensor issue. Any guidance on checking individual wheel speed sensors, verifying wiring integrity, or addressing the C0267 pump motor circuit would be greatly appreciated.

Related fault codes
C0227C0237C0238C0267
Comments (4)
Anonymous 2014-09-29 12:00

C0227: Left Front Wheel Speed Signal Erratic C0237: Rear Wheel Speed Signal Circuit Erratic C0238: Wheel Speed Mismatch C0267: Pump Motor Circuit Open - Are the tires identical in size and tread? The 'erratic' term suggests a potential sensor signal issue—check each wheel speed sensor's output. - For C0267, start with checking fuses and refer to the vehicle-specific wiring diagram.

Anonymous 2014-09-29 21:57

Thanks for the detailed breakdown, Kev. That’s exactly what I needed. I just got this truck, and all tires were previously the same but severely worn and unevenly balanced. The previous owner replaced ball joints recently. I’ve now installed brand-new 31x10.50 tires with a full alignment check—everything is within specification. Since I had the codes read right after installing the new tires (at the tire shop next door), I suspect this might have triggered sensor inconsistencies. I’ll proceed by testing each wheel speed sensor signal and follow your advice on checking fuses and wiring diagrams.

Anonymous 2014-10-02 19:41

Update: Today, I jacked up the truck and manually spun each front wheel while probing the sensor connectors. I measured over 350mV on both front sensors—within expected range. Since I didn’t have a helper, I had to spin the wheels and hold the probes simultaneously. I’m now considering clearing the codes and monitoring whether they reappear. If so, I’ll investigate further with the C0267 pump motor circuit issue next.

Anonymous 2014-10-17 09:21

Update: Since this problem existed before I purchased the truck, I bought my own Actron 9580A scanner and cleared all codes. After driving about 20 miles with no warning lights on, I parked for 20 minutes. When I restarted the vehicle, both the ABS and brake lights remained illuminated. I checked the system again and now only have C0238 — Wheel Speed Mismatch. The tool suggests a common fix is to reprogram the Powertrain Control Module (PCM). Is there a known troubleshooting guide or step-by-step procedure available for resolving this specific C0238 code? Any recommendations on how to verify sensor signals or perform PCM programming?