E045

Code E045 - Oxygen Sensor Circuit (Rich Exhaust Indication):

Wiring Diagram for Code E045 - Oxygen Sensor Circuit (Rich Exhaust Indication):

CODE E045 - RICH EXHAUST INDICATION

Circuit Description:

The ECM supllies a voltage of about 450mv between terminals "D7 and D6". (If measured with a 10 megaohm digital voltmeter, this may read as low as 320mv.) The O2 sensor voltage varies within a range of about 1 volt if the exhaust is rich, down through about 100mv if exhaust is lean.

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

Code E045 is set when:

a. Codes E033 or E034 not present
b. O2 voltage remains above 750mv for 2 minutes
c. TPS higher than 600mv or less than 300mv
d. Fuel system in closed loop
e. Closed loop integrator not forced to 128
f. All above conditions present for more than 120 seconds




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

1. Running the engine at 1000 RPM keeps the O2 sensor hot so an accurate display voltage is maintained.

2. Grounding CKT 412 should result in low O2 signal voltage display below 350mv. If the display is still fixed above 350 mv, the fault is a short to voltage in CKT 412 or the ECM is faulty.




Diagnostic Aids:

The Code 45 or rich exhaust is most likely caused by one of the following:

a. Fuel Pressure - System will go rich if pressure is too high. The ECM can compensate for some increase. However, if it gets too high, a Code 45 will be set. See Fuel System diagnosis.

b. Leaking injector - See Fuel System diagnosis.

c. Canister purge - Check for fuel saturation. If full of fuel, check canister control and hoses.

d. Pressure regulator - Check for leaking fuel pressure regulator diaphram by checking for the presence of liquid fuel in the vacuum line to the regulator.

e. TPS - An intermittent TPS output will cause the system to go rich due to a false indication of the engine accelerating.

f. O2 Sensor contamination - Inspect Oxygen Sensor for silicone contamination from fuel, or use of improper RTV sealant. The sensor may have a white, powdery coating and result in a high but false signal voltage (rich exhaust indication). The ECM will then reduce the amount of fuel delivered to the engine, causing a severe surge driveability problem.