Diagnostic Aids

Code 45 or rich exhaust is mostly caused by improper fuel pressure, HEI shielding, canister purge, MAP sensor, TPS, O2 sensor contamination, or EGR system. An O2 sensor heater failure will also set Codes 44 or 45. To diagnose components, refer to I - SYS/COMP TESTS article in this section.

If code is intermittent, see TESTS W/O CODES article in this section.

Fig 1: Code 45 Schematic (GSi), Heated O2 Sensor Circuit Rich Exhaust Indicated

Fig 2: Code 45 Flow Chart (GSi), Heated O2 Sensor Circuit Rich Exhaust Indicated