Mechanics

CHEVY ABS LIGHT

2001 Chevrolet Malibu

Brakes problem
2001 Chevy Malibu 6 cyl Front Wheel Drive Automatic

I have a '01 malibu. ABS light was on for a very long time. No problems driving, just no ABS. Decided to finally fix problem, got 2 new Hub Assemblys, replaced them. Light went away but came back as soon as car was in gear (other than Park and/or Neutral). Got the codes cleared/reset, light is still on when car goes in gear. Codes are: C1221, C1226, C1232. Wiring issue or something else?
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Ottawaman
May 12, 2010.




DTC C1221, DTC C1222, DTC C1223, DTC C1224: WHEEL SPEED SENSOR INPUT SIGNAL IS ZERO, DTC C1225, DTC C1226, DTC C1227, DTC C1228: RAPID VARIATION IN WHEEL SPEED SENSOR, DTC C1232, DTC C1233, DTC C1234, DTC C1235: WHEEL SPEED SENSOR SHORT TO VOLTAGE OR GROUND, OR OPEN
Perform diagnostic system check. See DIAGNOSTIC SYSTEM CHECK under DIAGNOSIS & TESTING. After performing diagnostic system check, go to next step.
Install scan tool. Turn ignition on. Set up scan tool snap shot feature to trigger for this DTC. Drive vehicle at speed greater 5 MPH. If scan tool indicate that this wheel speed DTC is set, go to next step. If scan tool does not indicate that this wheel speed DTC is set, problem is intermittent. See INTERMITTENTS & POOR CONNECTIONS under DIAGNOSIS & TESTING.
Raise and support vehicle. Disconnect affected wheel speed sensor harness connector. Using a DVOM, check resistance across wheel speed sensor connector terminals. If resistance is 850-1350 ohms on " W" Body (1040-1160 ohms on except " W" Body), go to next step. If resistance is not 850-1350 ohms on " W" Body (1040-1160 ohms on except " W" Body), go to step 8.
Manually spin wheel. Measure AC voltage across wheel speed sensor. If voltage reading is greater than 100 mV, go to next step. If voltage reading is not greater than 100 mV, go to step 8.
Check for poor connections at wheel speed sensor harness connector. Repair as necessary. After repairs, go to step 10. If connections are okay, go to next step.
Disconnect EBCM harness connector. Install Universal Pinout Box (J-39700) using Cable Adapter (J-39700-99) to EBCM harness connector only. Check wheel speed sensor circuits for open, short to ground, short to voltage or shorted together. Repair as necessary. After repairs, go to step 10. If circuits are okay, go to next step.
Check EBCM harness connector for poor connections. Repair as necessary. After repairs, go to step 10. If connections are okay, go to step 9.
Replace wheel speed sensor. After replacing sensor, go to step 10.
Replace EBCM. After replacing EBCM, go to next step.
Using scan tool, clear DTCs. Recheck DTCs. If DTC resets, go to step 2. If DTC does not reset, system is okay.
DTC C1236: LOW SYSTEM SUPPLY VOLTAGE
Perform diagnostic system check. See DIAGNOSTIC SYSTEM CHECK under DIAGNOSIS & TESTING. After performing diagnostic system check, go to next step.
Install scan tool. Start engine. Using scan tool, observe switched battery voltage parameter in ABS data list. If scan tool indicates voltage is greater than 10.5 volts, diagnose charging system. See STARTING & CHARGING SYSTEMS article in ACCESSORIES & EQUIPMENT. If voltage reading is not greater than 10.5 volts, go to next step.
Using scan tool, observe battery voltage parameter in the BCM data list. If scan tool indicates that voltage is greater than 10.5 volts, go to next step. If voltage reading is not greater than 10.5 volts, diagnose charging system. See STARTING & CHARGING SYSTEMS article in ACCESSORIES & EQUIPMENT.
Turn ignition off. Disconnect EBCM harness connector. Install Universal Pinout Box (J-39700) using Cable Adaptor (J-39700-99) to EBCM harness connector only. Check EBCM ground circuits including EBCM ground for open or high resistance. Repair as necessary. After repairs, go to step 7. If circuits are okay, go to next step.
Reconnect EBCM harness connector. Turn ignition on, with engine off. Using scan tool, clear DTCs. Recheck DTCs. If DTC resets, go to next step. If DTC does not reset, problem is intermittent. See INTERMITTENTS & POOR CONNECTIONS under DIAGNOSIS & TESTING.
Replace EBCM. After replacing EBCM, go to next step.
Using scan tool, clear DTCs. Recheck DTCs. If DTC resets, go to next step. If DTC does not reset, system is okay.

BMRFIXIT
May 12, 2010.


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