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Service Throttle Soon......What the?

If you have no SES or GP light then you have no PCM power. Your PCM is doing funky things, so its power from IGN, its grounds or its just flaky.
 
Ignition switch replaced and still having problems. SES light working as it should. GP and STS lights weren't coming on when it wouldn't start, but would when it would start.
 
Badaxe said:
Ignition switch replaced and still having problems. SES light working as it should. GP and STS lights weren't coming on when it wouldn't start, but would when it would start.
Click to expand...

Did you remove, inspect and clean all the fuses large and small?

I would even remove the ECM, check out all harnesses, and re-install. You may have a wire/connection ready to fail somewhere if you are positive your grounds are perfect.
 
Well it finally stopped cooperating. On the way to peruse the junk yards it died just three miles from home. It will crank but getting no SES, STS, or GP lights at all. One of the most frustrating parts is that it cost me $85 just to get it towed back the 3 miles. Dropped in spare PMD and no change. Pulled ECM and nothing noticeable. Seems as simple as a fuse but can't find it. I really need to find a decent repair manual. Need help fast.

dangerous- 138K It really has been a great truck even with the current issues. I plan to fix it and run it for at least another 16 yrs.
 
How well did you do/check the grounds on the rear stud/tranny dip stick?

Do yourself a favor....Remove all the grounds on the back of the engine, put new connectors on, clean and tighten......This way you can rule that OUT.
 
Did you check the ECM and gauges fuses under the steering column?

Check for power at the ECM fuse with the IGN on. Need to do some diagnostic probing before swapping parts.

Sounds just like a ground terminal cracking and breaking off on the back of the passenger side head.
 
I'd even go as far as to get some thick wire (I used old dryer cords, Using 2 of the 3 wires inside. I went from block to frame, and block to cab.

The braided ground strap that goes by the downpipe will just burn out and fail even if you replace. I've been there.

I routed my block to frame to the same bolt that holds the brake line a little forward of the front tire. I also did negative DS battery to frame on the other side.

Redundency, yes. But these things are super ground sensitive, as you know.

Now that it wont start its actually easier to fix IMO. This is a good thing. The tow sucks, but it is what it is.

Try this, cycle the key off and on a bunch of times and see one of those times the WTS and other lights come on.

When you swapped out the Ign module all the contacts looked fine?
 
Then get a helper, have then turn the key on, and you go nuts wiggling and jiggling wires, fuses, and anything else until that magic light comes on.
 
Grounds cleaned, fuel flowing, engine cranks, fuses under dash good, and no fusible links gone bad. Still no SES, STS, GP lights.
 
If you take out the PCM, disconnect the harnesses, and measure the voltage and grounds and they are all there and still no SES light then the PCM is bad or EPROM not seated or fried. I have an extra PCM you can try if you run these tests.

Pin PC1 should be continuity to ground, 32-pin pink connector wht/blk wire
Pin PD1 should be continuity to ground, 32-pin pink connector tan/wht wire
Pin PA1 should have 12V when IGN is ON, 24-pin pink connector, pnk/blk wire
Pin BD1 should always have 12V on it, 32-pin blue connector, orange wire

Both grounds come from them on the back of the block, and is shared with the OBD DLC connector pin A (top right). So there should be good continuity (less than 1 ohm) between any ground pin and truck chassis. Youre measuring ohms in that.

For the voltage measure between each power pin and ground and make sure there is 12V.



The battery feed shares the orange wire with the OPS and fuel pump relay.
 
Went to overhaul grounds this AM, still going to, to humor myself turned the key and it started up. A little reluctantly but started. Now off to rebuild the grounds.
 
All terminals and grounds got an extreme overhaul today with redundant grounds put in. Replaced a worn out fuse or two. So far so good. After the tow bill the wife won't let me go too far until we get AAA or a friend is available to rescue me.
 
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