Applied vehicles:

2004 Maxima (A34)
2004 Quest (V42)
2004-’05 Altima (L31) with VQ35 only

Concern:

An MIL “On” with one or more of the following DTCs stored:

• P0300, P0301, P0302, P0303, P0304, P0305, P0306 (cylinder misfire); or

• P1273, P1283 (A/F ratio lean).

Action:

Injector resistance may cause one or more of the above listed DTCs to be set.

• Check the resistance of the injectors against the values in this bulletin.

Note: Incident injectors will have resistance ­values:

– outside of the specified range indicated in

this bulletin and

– will be significantly different from the non-incident injectors at the other cylinders.

Important: The purpose of the Action is to give you a quick idea of the work you will be ­performing. You must closely follow the entire Service Procedure as it contains information that is ­essential to successfully completing this repair.

Service Procedure:

Use Chart 1 to determine which ­injectors to inspect.

 

DTC 1273 = Bank 1 (requires checking only that bank)

1. Locate and separate the F44 engine harness connector from the F101 injector sub-harness ­connector. See Fig. 1.

2. Using Chart 1 and the pin location in Fig. 2, measure the resistance of the ­injector(s).

 

DTC 1283 = Bank 2 (requires checking only that bank)

Important:

• Replace an injector only if its resistance is outside of the above range and the resistance is much different from the resistance of the other injectors.

– A single injector usually causes this incident. If more than one injector has resistance values out of specification:

– there might be a general problem with the accuracy of the resistance measurement, or

– component (injector) temperature condition may be high or low, or

– the vehicle is not of the ­applicable range.

DTC P0301-P0306 requires checking a single injector.

(refer to Chart 1 and the procedures used in DTC P1273 or P1283)

 

DTC P0300 (requires checking all injectors)

(refer to Chart 1 and the procedures used in DTC P1273 and P1283).

Note: It’s possible that a single injector incident:

– can affect the air/fuel sensor control for a bank of cylinders, and

– this can result in a P0300 code.

If the resistance of all the injectors is within 11.5 to 15.5 Ohms at 50-190° F (10-88° C), and the engine temperature is in the room temperature to engine warm temperature range, return to ASIST for further diagnosis.

Courtesy of Mitchell 1.