FixVault
Home › Saturn › 2002 › L100 › Repair and Diagnosis › Engine Performance › System › Engine Controls - Self-Diagnostics › Diagnostic Tests › DTC P0135: Ho2S1 Heater Performance › Diagnostic Procedures

Diagnostic Procedures

  1. Turn ignition OFF. If engine has been operating, allow engine to cool for about 30 minutes to ensure HO2S1 has cooled down. Turn ignition ON, engine OFF. Using scan tool, command HO2S1 on for one minute. If reading gradually changes towards zero volts, problem is intermittent. See DIAGNOSTIC AIDS  . If reading does not gradually change towards zero volts, go to next step.
  2. Check EIS fuse (10-amp) in under hood fuseblock. Replace fuse and retest if open. If fuse continues to open, check for a short to ground in Pink wire between under hood fuseblock and HO2S1 or for shorted HO2S1 heater. Disconnect HO2S1. Turn ignition ON, engine OFF. Connect a test light between HO2S1 connector terminal "D" (Pink wire) and ground. If test light is on, go to next step. If test light is off, repair open in Pink wire between under hood fuseblock and HO2S1.
  3. Turn ignition OFF. Disconnect PCM connector J2. Using a DVOM, measure resistance of Dark Green wire between PCM and HO2S1. If resistance is less than 2 ohms, go to next step. If resistance is not less than 2 ohms, repair open in Dark Green wire.
  4. Using a DVOM, measure resistance of HO2S1 heater. If resistance is 10-15 ohms, check terminals. If terminals are okay, replace PCM. If resistance is not 10-15 ohms, replace HO2S1.
About FixVault