Diagnostic Aids
Code 45 is most likely caused by one of the following; M/C solenoid does not click with ignition on and ALDL terminal grounded, and there is no Code 23, check for sticking solenoid. Check fuel evaporation canister for fuel saturation. MAP sensor output that causes ECM to sense a higher than normal manifold pressure (low vacuum) can cause the system to go rich. Disconnecting the MAP sensor will allow the ECM to set a fixed value for the MAP sensor. Replace MAP sensor if rich condition is gone while MAP sensor is disconnected. An intermittent TPS output will cause the system to go rich, due to a false indication of engine accelerating. Check O2 sensor for silicone contamination from fuel or use of improper RTV sealant. The sensor may have white, powdery coating and result in a high but false signal voltage (rich indication). The ECM will then reduce the amount of fuel delivered to the engine, causing a severe surge driveability problem. If code is intermittent, see TESTS W/O CODES article. If EGR valve is stuck open, it may result in a rich exhaust indication and could possibly set a Code 45, especially at idle. A faulty reed valve in AIR system can also cause a problem.