tj97dodge

No tach, speedometer, OD off, CC, wait to start light, seems to be in limp mode. Anybody seen this before?

TxDiesel007

probably ur PCM as a worst case

I lost my gauges when my pcm died on my truck. Lets just pray taht it is your engine control fuse on the truck, (pink 30 amp fuse under the box by driver battery) and not your pcm.. Cruise control can be a blue wire under the battery that has been disconnected or has corroded.

Tx

Fat1111

When I lost my cruise in my 97 it turned out to be a vacumn hose next to the battery. But that doesnt explain anything else.

tj97dodge

Checked all fuses and fusible links. Checked connections at sensors. Checked for 12 V at pcm, have it with truck running or not. Do not have 5 v at vss, ess, tps, or wif. Checked for 5 v at pcm thinking they are A 17 and B 31 A 17 being vio/wht and B 31 gry/yel. Can anyone verify these wire colors for me, I don't have a fsm, will get one very soon. Since I didn't have 5 v at sensors, and I need my truck for work. I cut what I'm thinking the 5 v wires are to see if pcm is putting out 5 v , no 5 v . Thinking I have a bad pcm. Opinions needed. Don't want to buy a pcm if not needed.

kd460

Sounds like your ESS (engine speed sensor).

See this post:

https://www.dieseltruckresource.com/...ad.php?t=73036

Read all 3 pages, tons of great info. First clean the ess with contact cleaner, then check the gap with a non magnetic feeler gauge, then if still not fixed, check the onnections and inspect the wires.

If you read that post, then you will know what to do.

infidel

Have you removed the connector for the pcm and probed it for voltages?
If so it is very possible that you enlarged the female pins and they are no longer making proper contact. Very easy to do and time consuming to fix.
You have to take the connector apart and squeeze the connectors back smaller.

A bad key switch can also mimic a bad pcm. Even if you get good voltage readings the pcm requires a steady voltage supply. "Flickering" that a voltmeter can't measure fast enough will mess the pcm up.

The pcm has internal circuit breakers that will shut it down if there are any shorts to ground at a sensor or in a wire loom.

I only know two people who have replaced the pcm and had electronic problems such as yours cured. Now they have an extra pcm. The pcm is tough unit that rarely fails.

For this type of problem the Powertrain Diagnostic Manual is better than the Factory Service Manual and costs less than $15.
Buy here https://techauthority.gltghosting.co...atalogId=10051
Most dealers are clueless about pcm problems, don't expect help there.

tj97dodge

Since I don't have the 5 volts at the sensors, I don't see why it would be the ess. Also I cut the 5 volt out lines from the pcm and tested, no 5 volts. Help??

tj97dodge

After all the testing figured it was the pcm. Ordered a used pcm, took a couple days. Put it in, not fixed. Figured it needed to be programmed. Dodge said their equipment will only put in new vin can't change vin, so used pcm was no good to me. Took used pcm back, ordered reman pcm which they preprogrammed with my vin, truck is back in business. I appreciate all the replies I had. I joined a couple of places to help me with this, and this was the best group. Thanks guys!!!!

royta

Bummer. I have a brand new PCM with about 15 minutes of use on it. I would have loved to have sold it to you for a fraction of what I paid for it.

Glad you got it fixed!

infidel

Next time take your used pcm to Cummins, not the dealer.
They are able to reflash them to whatever year/model you have.

jimk

Bill can Cummins reflash the pcm on my 95 to raise shift point of overdrive and lockup from 45 to 55 or better yet 60. I have been told some are reflashable and others not. I grow tried of using the overdrive button every time to do that. Thanks Jim

infidel

Pre '97 isn't OBD and needs a Chrysler scan tool to reflash. If you can find a dealer that still has the tool and a mechanic there who knows how to work it it can be done.