Diagnosis & Repair

NOTE: Read freeze frame data using hand-held tester or OBD II scan tool, as freeze frame data records engine conditions when a malfunction is detected. When trouble shooting, it is useful for determining whether vehicle was running or stopped, engine was warmed up or not, air-fuel ratio was lean or rich, etc. at time of malfunction.

For wiring diagram, see DTC P0125: INSUFFICIENT COOLANT TEMPERATURE FOR CLOSED LOOP FUEL CONTROL .

Read output DTC (besides P0136). If only DTC P0136 is output, go to next step. If DTC P0136 and other DTCs are output, go to DIAGNOSTIC TROUBLE CODE DEFINITIONS .
Check harness and connector between ECM and oxygen sensor. See ENGINE PERFORMANCE in SYSTEM WIRING DIAGRAMS article in ELECTRICAL. If results are OK, go to next step. If results are not good, repair or replace harness and connector.
Read value of hand-held tester (output voltage oxygen sensor).
1. Connect hand-held tester or OBD II scan tool to DLC3. See Figure.
2. Warm up engine to normal operating temperature.
3. Read voltage output of heated oxygen sensor when engine is suddenly raced.
Perform a quick racing to 4000 RPM 3 times using accelerator pedal. If heated oxygen sensor output voltage alternates from 0.4 V or less to 0.5 V or more, check that each connector is properly connected. If voltage is not as specified, replace oxygen sensor. See REMOVAL & INSTALLATION - 4-CYLINDER article.