Power Reduction/Service Engine/Will not start

[degenemon]

I have a 2002 Saturn Vue 4 cyl manual transmission. The other day I was driving home and right after coming up to speed my Vue lurched and the a Power Reduction light came on. I saw the RPMs drop and then thought "what is power reduction" as I have never heard of this. In the time for me to look down and think what is that the SE light came on and my Vue cut off. I pulled over and got a tow home and called by neighbor who is a mechanic. He brought over a diagnostic code reader and everything is passing, but the car will not start. Any ideas? I tried to search the forums for this issue, but came up empty. Sorry if this has been posted. Thank you to anyone who can offer advice.

[VueGuy168]

there is a sensor wire behind the throttle body on the engine. if this is not plugged in all the way or loose, you will not be able to accelerate. At least this is how mine is on the v6.

[fdryer]

1-Does the engine turn over at all? Turning the engine over at least indicates that the battery and starter work and troubleshooting goes in one direction.

2-If the engine does not make a sound after turning the ignition key to the START position indicates troubleshooting in another direction.

3-With the ignition in the ON/RUN position, are the only indicator lights the battery (red), oil (red), E-brake (red), and seat belt (red)? There shouldn't be any other lights on.

[degenemon]

1-Does the engine turn over at all? Turning the engine over at least indicates that the battery and starter work and troubleshooting goes in one direction.

2-If the engine does not make a sound after turning the ignition key to the START position indicates troubleshooting in another direction.

3-With the ignition in the ON/RUN position, are the only indicator lights the battery (red), oil (red), E-brake (red), and seat belt (red)? There shouldn't be any other lights on.

1-The engine does turn over, but it is very weak.

3-The SE light is also on.

Thank you both for your input.

[fdryer]

Find a way to charge the battery overnight as you'll need it asap unless you can boost it from another battery. Having the SES light ON should mean that any codes would be displayed on most reader/scanners. This would be most helpful for troubleshooting otherwise it makes it more difficult to figure out.

Another difficulty to troubleshooting at home is that your ignition system is hidden using ignition modules and an ignition coil pack for neatness, eliminating the spark plug wires for troubleshooting purposes. One way to find this engine-turns-over-but-never-fires-up problem is to look for sparks, either across conventional ignition coils or from the spark plugs removed from the engine but connected to the ignition system. Troubleshooting your ignition system to test for spark would entail removing the ignition module, ignition coil pack, and spark plugs and reassembling them externally, connecting the wiring and grounding the plug bases to enable observation of any spark across any plug while cranking the engine over. A tedious test.

The whole idea of this test is to isolate a crank position sensor, ignition module or ignition coil pack fault. The toss-up is either a cps or ignition module. The ignition module can be tested by someplace like Autozone (call ahead to verify) while measuring the cps for resistance with a multimeter can determine a failure. These two methods are alternatives to the rigamarole described above. The cps is near the starter and should measure around 800-1500 ohms. This cps is the electronic equivalent of the heartbeat for the EFI system without which the entire EFI system is dead. The ignition module provides the high voltage spark and does fail from time to time as reported by previous posts for the 2.2L engine.

[far2grumpy]

This is not going to be much help but I found a reference to reduced power mode in the service manual.

See attached file.