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Home >> Chevrolet >> 1999 >> Forward Control P12 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System - Tests W/Codes - DTC P0135-P0204 >> DTC P0141 >> DTC P0141: Ho2S Heater Circuit-Sensor 2 (1.9L SATURN) >> Diagnostic Procedures

Diagnostic Procedures

  1. Install scan tool. Start engine. Using scan tool, command O2S heater on while observing rear O2S current. If rear O2S reading is 0.5-2.4 amps, problem is intermittent. See DIAGNOSTIC AIDS . If rear O2S reading is not 0.5-2.4 amps, go to next step.
  2. If reading is greater than 2.4 amps, go to next step. If reading is less than 0.5 amp, go to step  5.
  3. Disconnect H02S 2 harness connector. If reading is now is zero amps, replace HO2S 2. If reading is not zero amps, go to next step.
  4. Disconnect PCM harness connector J3. If reading now is zero amps, repair short to battery voltage in circuit between HO2S 2 terminal "B" and PCM. If reading is not zero amps, check circuit between ground and PCM and ground circuit between PCM and ignition switch. Repair as necessary. If circuits are okay, replace PCM.
  5. Disconnect HO2S 2 harness connector. Using a fused jumper wire, jumper HO2S 2 harness connector terminals "B" and "D". If reading now is greater than 0.5 amp, repair poor connection to HO2S 2. If connection is okay, replace HO2S 2. If reading is not greater than 0.5 amp, go to next step.
  6. Check voltage at HO2S 2 harness connector terminal "D". If battery voltage is not present, repair open in circuit. If battery voltage is present, check for short to ground or poor connection between HO2S 2 harness connector terminal "B" and PCM. Repair as necessary. If circuit is okay, replace PCM.
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