P046

Diagnostic Trouble Code Chart P046:

Fuel Injector Circuit:

CIRCUIT DESCRIPTION
The Powertrain Control Module (PCM) controls rear bank fueling based on the rear oxygen sensor and front bank fueling based on the front oxygen sensor. Code P046 sets when the front bank fueling differs greatly (richer or leaner) from rear bank fueling for 10 minutes.

LIKELY CAUSES OF CODE P046 ARE:
1. Lean or faulty injectors on one side of the engine.
2. Cracked or fouled spark plugs.
3. Exhaust or intake manifold leak.

TEST CONDITION
Test continuously.

FAILURE CONDITIONS
Front bank fuel control long term fuel trim values differ from rear bank fuel control long term fuel trim values by more than 15 counts for 10 minutes.

ACTION TAKEN
PCM turns "ON" the Malfunction Indicator Lamp (MIL) (Service Engine Soon).

NOTES ON FAULT TREE
1. If any other codes are set, diagnose them first because they can cause a fueling imbalance.
2. Checking for a physical/mechanical problem causing P046 to set.
3. The bank that is the farthest from the neutral value of 128 is the bank which is out of fuel control. (Refer to PD38 and PD39 data description for more information on the neutral value of 128.)