pcmhacking.net

Not strictly a tuning question but:
My VT 5.0 has just brought up error code 53. Battery voltage was 13.8 volts measured with a multimeter. So I disconnected the belt and the electrical connectors from the back of the alternator, started the engine and the code is still there.
So is this code cleared by disconnecting the battery?
Any one else have any experience with this error code? My understanding is that this is generally considered to be a charging system fault.

Thanks in advance

yeah disconnect the battery and then re-check to see if the code re-appears.

Sorry, should have mentioned.
I had the battery disconnected when I pulled the belt and removed the electrical connectors off the alternator. So it should have reset then but he check light stays on with the Code 53 still active.

DTC 53:
SYSTEM VOLTAGE TOO HIGH
Diagnostic Trouble Code (DTC) 53 will set when the ignition is ON and PCM terminal C1 voltage is greater than 19.5 volts for about 2 seconds.
During the time failure is present, the pressure control solenoid is turned OFF, the transmission shifts immediately to 3rd gear and TCC operation is inhibited. Additional codes may also set.

Test Description: Number(s) below refer to step(s) on the diagnostic chart.
2. Normal Battery voltage is between 9.6 and 14.5 volts.
3. Checks to see if the voltage reading is due to the generator or the PCM. With the engine running, check voltage at the battery. If the voltage is above 14.5 volts, the PCM is OK.
4. Checks to see if generator is faulty under load condition. If the voltage is above 14.5 volts, refer to Section 6D2-1, CHARGING SYSTEM - V8 ENGINE in Volume 3 of the VR Series Service Manual.

So if battery voltage is fine with the ignition switched on but engine not running, theres no real opportunity to have 19.5 volts at the PCM. So the only other possibilty is a faulty PCM???

id check the voltage at that pin, but yes quite possible.

I had an issue with my car a while back every now and then the motor would drop revs for a bit then back up to normal, couldn't figure it out for ages, then one time I had the multimeter on the battery when it did it, was putting 17.5 volts into the battery!

turns out a new regulator and viola!

Yeah voltage reg would be high on the list to check. Try clearing the code via ALDL and see if it returns and maybe monitor ALDL to see what the battery voltage is doing - can possibly compare inj monitor and battery voltage to determine if its a PCM fault.

It's on its 3rd regulator now since new and as I need to change to a vee belt drive instead of the 4pk belt, figured a new alternator would be the go. I've ordered a new alternator over a week ago and was hoping it would have been here by now.

I can't start the engine just at the moment but on the Data List the injector and battery voltages read within 0.1 volts of each other jwith the ignition on. I am still trying to figure out how to view and clear DTCs via Tunerpro but I'll get there.

why did you go backwards and fit a V-belt the serpentine belt was one of the best things they did to the 304