E013

Code E013 - Open Oxygen Sensor Circuit:

Wiring Diagram for Code E013 - Open Oxygen Sensor Circuit:

CODE E013 - OPEN OXYGEN SENSOR CIRCUIT

Circuit Description:

The ECM supplies a voltage of about 450 mv between terminals, "D6" and "D7". (If measured with a 10 megaohm digital voltmeter, this may read as low as 320 mv.) The O2 sensor varies the voltage within a range of about 999 mv if the exhaust is rich, down through about 100 mv if exhaust is lean.

The sensor produces no voltage when it is below 360°C (600°F). An open sensor circuit or cold sensor causes open loop operation.

Code E013 is set when:

a. The engine has run for 40 seconds.
b. No Code E021 or E022 present.
c. The coolant temperature is above 42.5°C (109°F).
d. The voltage at terminal D7 of the ECM stays within a range of 350 to 557 mv.
e. The TPS is 6% above idle (.9 to 1.0 volts).
f. Conditions last for 60 seconds consecutively.




Test Description: The following numbered steps correspond with the steps numbers on the diagnostic chart.

1. Allowing engine to run under these conditions will give a normally operating O2 sensor sufficient time to cause system to run "closed loop." If open loop (0) is displayed constantly, further testing is necessary as fault is present.

2. Grounding the O2 sensor signal circuit will cause the display to read near zero if the PROM or ECM and circuitry are ok. This would indicate a faulty sensor. If display stays near 450 mv then an open circuit exists or the PROM or ECM is at fault.

3. If CKTs 412 and 413 are not open and ECM is functioning properly, then 300-600 mv would be present.




Diagnostic Aids:

An intermittent may be caused by a poor connection, rubbed through wire insulation or a wire broken inside the insulation.

Check For:

a. Poor Connection or Damaged Harness - Inspect ECM harness connectors for backed out terminals "D7" OR "D6", improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wire connection and damaged harness.

b. Intermittent Test - If connections and harness checks out ok, monitor ED07 (O2 Sensor Voltage) display while moving related connectors and wiring harness, with warm engine running at part throttle in closed loop. If the failure is induced, the "O2 Sensor Voltage" reading will change from its normal fluctuating voltage (above 600 mv and below 300 mv) to a fixed value round 450 mv. This will help to isolate the location of the malfunction.