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HOMESERVICE MANUALSPONTIAC1983GRAND PRIX BASE, 5.0 HREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 11 (FEEDBACK CARBURETOR TESTS W/CODES)CODE 45: RICH EXHAUST INDICATION
1983 Pontiac Grand Prix Base, 5.0 H

Code 45: Rich Exhaust Indication

1983 Pontiac Grand Prix Base, 5.0 HSECTION Code 45: Rich Exhaust Indication
WARNING: This page does not describe the selected car, but rather 28 other vehicles, including the 1984 Pontiac Phoenix, 1984 Pontiac Parisienne, 1984 Pontiac Grand Prix, 1984 Pontiac Firebird, and 1984 Pontiac Bonneville. However, it is still accessible from the selected car via links, so may be relevant.

Code 45 indicates that the ECM has seen:

  • High oxygen sensor voltage.
  • More than specified time (about 2 minutes).
  • Above a specified TPS value.
  • Closed loop.

A high voltage can be caused by a rich exhaust or an O2 sensor contaminated with silicone.

NOTE: The following step numbers refer to the numbers in the accompanying flow chart(s).
  1. Dwell under 50° indicates that engine should be checked for cause of intermittent rich condition; purge or bowl vent valves leaking, fuel in crankcase, fuel in evaporative canister, or sticking mixture control solenoid metering rods.
  2. This step tests ECM response to a lean engine condition. A drop in dwell indicates that ECM and O2 sensor are not faulty.
  3. This step tests ECM response to a lean O2 signal (low voltage). If no dwell change with a grounded lead to O2 sensor term. 9", fault is in ECM. Open O2 sensor wire would have set Code 13.
  4. This step checks voltage from the ECM at the O2 sensor harness. Normal voltage at this point is the ECM bias voltage for no O2 signal, approximately .45 volt. If voltage is high, the wire to the ECM could be shorted to battery voltage, or ECM is faulty.
Fig 1: Code 45: Rich Exhaust Indication Flow Chart
G9321
RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.