DTC P1133: Front Ho2S Heater Circuit High Input - Forester, IMPREZA, Legacy & Outback 2.5L M/T & Outback Sport
- Perform basic diagnostic procedure. See BASIC DIAGNOSTIC PROCEDURE . Turn ignition on. Using DVOM connected to ground, backprobe ECM connector B134 (35-pin connector) terminals No. 22 and No. 23. See Figure. If voltage is more than 8 volts for both checks, locate and repair short to voltage in wiring between ECM and front HO2S and then go to next step. If voltage is not more than 8 volts for both checks, go to step 3.
- Turn ignition on. Using scan tool, observe front HO2S heater current value. If front HO2S heater current draw is more than 2.3 amps, replace ECM. If front HO2S heater current draw is not more than 2.3 amps, test is complete.
- Using DVOM connected to ground, measure voltage at ECM connector B134 (35-pin connector) terminal No. 23 while wiggling harness and ECM connector. If voltage does not change more than 8 volts while wiggling harness and ECM connector, go to next step. If voltage changes more than 8 volts while wiggling harness and ECM connector, locate and repair short to voltage in wiring between ECM and front HO2S. See WIRING DIAGRAMS article.
- Using DVOM connected to ground, measure voltage between ground and ECM connector B134 (35-pin connector) terminal No. 22 while wiggling harness and ECM connector. If voltage changes more than 8 volts while wiggling harness and ECM connector, locate and repair short to voltage in wiring between ECM and front HO2S. If voltage does not change more than 8 volts while wiggling harness and ECM connector, test is complete. Clear memory and perform verification procedure. See CLEARING DIAGNOSTIC TROUBLE CODES and VERIFICATION PROCEDURE .