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OnlineHelp, Mechanic
Category: Car
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Experience:  Mechanic
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1999 Oldsmobile Aurora: Fuel filter, Spark plugs & wires..module

Resolved Question:

1999 Oldsmobile Aurora will not start!!! Fuel pump, Fuel filter, Spark plugs & wires, Ignition coil module and map sensor have been replaced!!! What is my problem??
Submitted: 7 years ago.
Category: Car
Expert:  OnlineHelp replied 7 years ago.

Hello and thank you for choosing Just Answer.


Does the car just turn and crank, but will not start?



Customer: replied 7 years ago.
Yes the car turns to try to crank but will not start.
Expert:  OnlineHelp replied 7 years ago.

Have you done a fuel test or spark test yet?


Have you been able to determine if the car does not get spark or fuel?




Customer: replied 7 years ago.
No I havent. Im not sure what is happening. I had a guy from the part store to stop by and run a computer diagnostic yeaterday and it showed a possibly bad ignition coil module and a bad map sensor. Both have been replaced. still no start!! What should I do!!
Expert:  OnlineHelp replied 7 years ago.

Do you remember the code that the guy gave you?


The code should have been a P#### (# XXXXX for numbers 0-9)



Customer: replied 7 years ago.
P1108 & P1376
Expert:  OnlineHelp replied 7 years ago.

Thank you.


I would not worry about the p1108 , the P1376 is what we need to focus on. The car does not have spark. This is due to "P1376....Reference voltage low, or ignition ground circuit"

Which does NOT mean that the ignition coil is bad, it means that the ground is low for the ignition circuit.


The frist thing I would do is check G101 (ground), it is located Lower passenger rear of Engine, below Power Steering Reservoir. Here is the diagram for it.


Also remove and reinstall connectors on PCM and ICM. Also, as per the diagnostic aid make sure the PCM is installed correctly.


Circuit Description

The PCM applies 2.5 volts on the Ref Lo voltage (CKT 453) circuit to the Ignition Control Module. Ref Lo voltage to the PCM represents the voltage difference between Ref Lo and the PCM power ground. This is needed to ensure that the PCM and IC module signals all have the same ground reference. If the Ref Lo input voltage goes too high or low, DTC P1376 will set.


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