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Home >> Isuzu >> 1999 >> Trooper Part Time >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Trouble Code Identification >> DTC P1134: Heated Oxygen Sensor (Ho2S) No. 1 Bank 1 Circuit Transition Time Ratio >> Diagnostic Aids

Diagnostic Aids

An intermittent problem can be caused by misrouted harness, rubbed-through wire insulation or broken wire inside insulation of HO2S heater circuit. If connections and wiring are okay and DTC continues to reset, replace HO2S 1. Check scan tool FAILURE RECORDS to determine mileage since last DTC was set.

  1. Perform On-Board Diagnostic (OBD) System Check. See BASIC DIAGNOSTIC PROCEDURES article. Read and record FREEZE FRAME and/or FAIL RECORDS data for each DTC set. Go to next step.
  2. If any DTC other than P1153 or P1154 sets, diagnose affected DTC before proceeding. If no other DTC sets, start engine and allow it to idle. Operate vehicle within conditions required to set DTC. Using scan tool, read SPECIFIC DTC. If scan tool displays DTC P1134 FAILED THIS IGN, go to next step. If scan tool does not display DTC P1134 FAILED THIS IGN, check for an intermittent problem. See DIAGNOSTIC AIDS .
  3. If DTC P1153 and/or P1154 is also set, go to step  11. If DTC is not set, go to next step.
  4. Check exhaust system for leaks. If exhaust leak is found, repair as necessary. Retest system. If no exhaust leak is found, go to next step.
  5. Visually inspect HO2S No. 1 for secure installation or corrosion on terminals. Check terminal tension at HO2S No. 1 and PCM. Check for damaged wiring. If a problem is found, go to step  8. If no problem is found, go to next step.
  6. Disconnect HO2S No. 1 connector. Turn ignition on. Using DVOM, probe connector, measure voltage between high signal circuit (Pink wire on 3.2L, or Red wire on 3.5L) and ground, and low signal circuit (Blue wire on 3.2L, or Green wire on 3.5L) and ground. If DVOM reads 3-4 volts, go to next step. If voltage is not as specified, go to step  9.
  7. Turn ignition off. With HO2S No. 1 disconnected, connect a jumper wire between HO2S No. 1 harness connector high signal (Pink wire on 3.2L, or Red wire on 3.5L), low signal circuit (Blue wire on 3.2L, or Green wire on 3.5L) and ground. Turn ignition on. If scan tool reading increases from .01 volt to .45 volt when jumper is removed, go to step  11. If voltage does not change as specified, go to step  12.
  8. Repair condition as necessary. Retest system.
  9. Check for poor PCM connections or terminal damage. Repair as necessary. Retest system. If no problem is found, go to next step.
  10. Repair open, grounded or shorted signal circuit (Pink and Blue wires on 3.2L, or Red and Green wires on 3.5L). Retest system. If no problem is found, go to step  7.
  11. Remove Bank 1 HO2S No. 1 and check it for fuel contamination, improper RTV sealant (white powdery coating on sensor) and engine oil or coolant consumption. Repair as necessary. Retest system. If no problem is found, go to step  13.
  12. Replace PCM. Retest system.
  13. Replace HO2S No. 1. Retest system.
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