SES Light Due To A P1174 DTC - Perform Injector Test With AFIT (CH47976)SES Light Due To A P1174 DTC - keywords active balance cylinder engine fuel lamp misfire miss P0300 tester

This PI was superceded to exclude models that are now covered in 08-06-04-001. This PI remains for the models that are not covered in the bulletin. Please discard PIP4017A.

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

On rare occasions, a SES light may be encountered due to a P1174 DTC. In some instances, a P0300 may also be stored. This may be due to a fuel injector concern on one of the cylinders that a Tech 2 fuel injector balance test may not isolate.

If the SI diagnostics do not isolate a cause for this concern, perform the Fuel Injector Diagnosis (w/CH47976) in SI. If a lean injector is found, replace it and re-evaluate the concern. In some instances, a fuel injector that has a flow rate as little as 3% less than the other 3 injectors could cause this DTC to set. Also, as mentioned in the P1174 SI diagnosis, if the misfire current counters or misfire graph indicate any misfires, it may be an indicator of the cylinder that is causing the concern.

Notice:  As mentioned in the AFIT User Guide, vehicles that are not listed in the AFIT menu can still be tested with the AFIT. If the model you are working on is not in the AFIT menu, ensure that the AFIT has been updated with the latest software. To find the latest AFIT software, take the following path: Go to GM Dealerworld Website>> GM Essential Tools - S/W updates>> AFIT Downloads. If the latest AFIT software has been installed but the vehicle you are working on still is not listed in the AFIT menu, it will be necessary to use the direct connection method outlined in the AFIT User Guide (See Pages 16-31).

Notice:  If interested, the June 2006 Edition of Techlink contains more information about the AFIT. To find this article, take the following path: Go to GM Dealerworld Website>> Click on the Service Tab in Dealerworld>> Click on the GM Techlink Hyperlink>> Click on the Archives Hyperlink at GM Techlink>> Click on 06-2006 in the Archives Section>> Click on the Active Fuel Injector Tester Link in the June 2006 Techlink Article.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.