Electrical problems...

[north42g]

2002 Protege5 2.0L. 99,911 miles.

Recently the electrical system has been acting up. The head lights & interior lights & engine idle are all surging together; The lights would go dim and then brighten up in sink with the engine idle. I used my DVOM to measure the voltage at the Battery: The results are 12.5v up to 18.3v, up & down like that. I thought it was a sign of a failing Alternator.
[The PCM recorded a DTC of P1632- Generator Voltage to PCM below 8.0v]
I ordered an Alternator from Maniac Electric Motors. Friday Night I Removed and Replaced the Alternator and Battery. No help. The same problem was happening.

The issue seems to subside when the heater fan is switched on. It also sounds like the A/C Compressor is cycling on/off when the Heater fan is turned on.

I read more about the DTC-1632 & that there is not sufficient voltage to PCM through wt/gr wire from fuse box.

Does any one have any further information about this issue? This is puzzling to me. I have been an Automotive Technician for 2.5 years now, and unfortunately electrical has never been a strong point.

Where is the PCM located in this car?(I don't have ALLDATA on my home computer) Is there a pin-point test available for DTC-P1632?
Can any of you guys point me in the right direction as to what may be the cause of this issue?

Thanks in advance!!!

 

[Pauljp]

DTC P1632 = Battery Voltage Monitor Signal Circuit Malfunction.
Detection Condition = PCM monitors voltage of backup battery positive terminal at PCM terminal 4. If PCM detects battery positive terminal voltage below 7.97 V for 5 seconds, PCM determines that backup voltage circuit has malfunction.
Possible Cause = 1. Open circuit in wiring between battery positive terminal and PCM terminal 4.
2. Poor connection of PCM connector.
3. PCM malfunction.

The PCM is located on the passenger side by the glove box. It has a monster 104 pin (4x26 pin) connector. You can't miss it.

Basically, it flows like this: Battery positive, through INJ 30A fuse to pin 4 (W/G wire) of the PCM.
I would clean everything first.
Soak your battery connectors in a mixture of baking soda and water to clean it up.
Inspect the INJ fuse to ensure it is nice and clean.
Inspect your PCM connector for corrosion or rust, put some dielectric grease on it to protect them and make sure it has a tight fit.
That's all I have for that DTC code.
Hope it helps.

 

[north42g]

thank you very much, the battery term are good & clean. I will run down the line and check every thing out to start with. Thanks again.

 

[north42g]

every thing seems to check out,
All though.. I "wiggle tested" the wt/gr wire from fuse block to pcm and the condition subsided!
looks like I will have to re-connect o clean up the connection1
thanks.