Codes 18, 35, 54

[Foehammer]

I was driving to pick my son up from school today and my truck stumble and kind of backfired and it threw codes 18, 35, 54 but after the momentary stumble it ran normally but codes didn't clear any thoughts i thought of maybe
doing a relearn of the pcm by unhooking battery for 60 secs but i need experet advice before i feel confident of what i should do
thanx in advance

 

[packratt]

Perform the checklist and post the results. http://www.dieseltowingresource.com/showthread.php?t=6300

Where do you have the PMD heatsink mounted?

 

[docdray]

codes found here: http://www.dieseltowingresource.com/showpost.php?p=50700&postcount=3 just curios, how old is your os filter harness, LP, original IP?

 

[Foehammer]

Problem: my truck stumble and kind of backfired and it threw codes 18, 35, 54 but after the momentary stumble it ran normally ____________________________

Demographics: tell us about your truck and your ambient conditions:

- Year: -1994
- Truck model and class (ie: c2500) -k1500
- Automatic or Standard -auto
- Mileage: (indicate miles or km) -185k miles
- Replaced parts and mods (IP, PMD, chip/PCM, TM, injectors etc) -ditech pmd installed in bumber on cooler 1 month ago
- Model: ‘S’ or ‘F’ engine, NA or Turbo, EGR? -s engine egr disabled
- Ambient outside temp: (indicate *C or *F) -76 F
- What fuel are you using? (#1 Diesel, #2 Diesel, Bio, VO, WVO, etc) -#2
- What fuel additives are you using? -8 oz tc-3w, 8oz powerservice white each fill up fill up at 1/4 tank
- Where are you located? -Las Cruces NM

General maintenance: inspect and evaluate the condition of each. When were they last changed?
- Air filter -2 months ago
- Fuel filter -1month ago
- CDR Valve? 2 months ago
- Coolant – last flushed/replaced at -unkown
- Oil – synthetic/regular, changed at - 6 months ago
- Batteries – state of charge, (matched set) replaced at -unknown
- Battery cables and grounds (removed, cleaned and tightened): -unknown
- Glow Plugs - how many miles on them? -unkownWhat type? - unknown
- Injectors - last changed at -unknown


History: (Describe how the problem first appeared.)
- What were you doing when it happened? driving 35mph up slight hill
- How was the truck running fine before this problem appeared? yes
- Has this problem ever happened before? no
- Describe any related factors that might be part of the problem. had a code 35 and 36 1.5 month ago with stumbling after i addedlubro moly diesel purge to tank i think it loosened up gunk in the tank
- Have you checked for DTC (Diagnostic Trouble Codes)? (Y.N) Y And? 18, 35, 54


Diagnostics:

1] Starting:
1a] Does the engine start? y
1b] Does the engine crank over? y
1c] Are your batteries fully charged? y
1d] Have you removed, cleaned, and tightened all battery connections? n
1e] Does your Wait to Start light come on for a time? How long? no wait to start light only glow plug light
1f] Does your glow plug light come on? y For how long? 10 secs
1g] Do you see smoke from the exhaust while cranking? What color? grey/black

2] Fuel Issues (if not running):
2a] Can you hear your lift pump working? ____________
2b] Do you get a steady flow of fuel from the water drain (T-handle) ? _________
2c] Loosen the inlet line from the IP – is fuel coming out (Lift Pump on)? ___________
2d] Loosen an injector line and crank the engine - does fuel come out? _________
2e] Do you hear a vacuum (hiss) when you remove the fuel cap? ___________

3] PMD / IP Issues
3a] Location of PMD (on pump, on intake, remote mounted) remote mount on cooler in bumper nostril
3b] Condition of Extension harness (if used) Vendor or Homemade? vendor
3c] Condition of grounds / ground wires to IP / PMD. Check Harness. appear good
3d] PMD Make: Ditech
3e] PMD Age: 1 month

4] Stalling Issues
4a] Do you experience stalling only when hot? n
4b] Does it stall under particular circumstances? (ie hit bump, or on accel) ______
4c] Does pouring cool water over the IP seem to help with restarting? n/a
4d] Is stalling momentary (engine recovers)? y
4e] Does SES light come on when engine hiccups? y
4f] Does cruise control quit working when engine hiccups? dont think so was driving straight tho
4g] Does re-starting seem to reset engine, restoring cruise and power? have not restarted yet
4h] Changes to dash lights or instruments during stalling events? n
5] Running Issues
5a] On cold start, does upper rad hose get hard before engine warms up? n
5b] Any bubbles or oil film in coolant overflow tank? unknown
5c] Any white slime on oil surfaces (dipstick, CDR, oil Fill cap)? n
5d] Excessive white smoke from exhaust on cold start? n
5e] Excessive black smoke from exhaust under hard acceleration? n

6] Performance Issues
6a] Do you have gauges? stock
6b] Maximum boost under load? no boost gauge
6c] Have you added a performance PCM (reflash) or Chip? n
6d] Have you changed exhaust / downpipe / crossover? n
6e] Wastegate – mechanical or vacuum? vac

7] Temperature-related Issues:
7a] Single or dual thermostats? single
7b] Have you replaced them lately? Manufacturer of replacements? n
7c] Have you pulled and cleaned Radiator and coolers lately? n
7d] Have you replaced the fan clutch? Manufacturer of replacement? n
7e] (winter) Have you tested your antifreeze? Good to what temp? __________
7f] (winter) Are you using a winter grille cover? ___________

 

[Foehammer]

docray i bought the truck 3 months ago so i dont known how old the lift pump is or the os filter harness but i believe the ip is original but not sure

 

[JMJNet]

May want to check your LP and OPS to answer Questions 2.

 

[buddy]

For a 54, the book says to replace the PCM if not with a 17. everything is running good now though and youre not getting a constant SES light? If you clear codes do they come back? When in diagnostic mode depress both pedals for 15 seconds at the same time, then see that you only get DTC12, then start it up and see if you get the codes back. It could be that the lines to the Optical Sensor (OS) shorted or broke. If you have a digital multimeter and are good with it I can get you some info on testing the circuit.

On a 94, to check OPS start truck up and check for 14V on pin G of the OBD1 port, bottom left. If no voltage OPS is not working.

To see if LP actually works without truck on, check the fuse on the passenger fire wall, then push the fuse top, where this is a slit, up on a battery junction post next to it. You should hear pump come on. Open up the valve by the thermostat and put the drain hose into a container and see that it flows healthy.

 

[Foehammer]

What i have done this evening so far is unhook the batteries (and clean all the connections) for 60 secs to force the pcm to "relearn" as well as clear the codes IU drove around for about 1/2 hour at various speeds and i got no codes so far :biggthumpup:

 

[JiFaire]

Grounds and the optical filter harness on the OS.

Almost certainly your issue, FH. Clean all your battery, frame, and engine grounds SUPER well as general preventative maintenance, and if that code comes back persistently, try removing the filter harness and just plugging things back in without one.

 

[Foehammer]

Thx JiFaire Ill try the optical sensorharness next ijust got finished with the grounds and battery terminal connections so far no reoccurence of the codes

 

[JiFaire]

General point to all 6.5 guys

I know the book says to replace the PCM for a number of complaints, but the book is wrong on that count. I can count on one hand the number of actual PCM failures I have heard about, and I only know of one. The PCM is a durable little chunk of solid-state stuff; it is fairly impervious to environmental concerns, it is seldom affected by the level of transient voltage the 6.5 will produce, and even welding on the frame is highly unlikely to disturb it.

So what would make errors pop up that the designers thought would be attributable to the PCM?

We discovered years ago something very simple that the engineers overlooked; electronic controls operate best when there is full circuit integrity - and certainly the engineers did NOT take that into account when designing the wiring and circuitry on the 6.5TD, or they would have made some very simple changes.

The electronics on these trucks use the vehicle ground as a backplane for some things, rather than isolating every circuit. While this may save a few dollars and headaches for the guys building the trucks, it creates timing problems and transient grounding issues in circuits that require continuity... engine/frame and frame/body grounds are especially problematic; rather than being bolted, these should have been bonded to the parts and plug-in on the harness, rather than bolt-on on both ends.

Pulling and cleaning every ground, at the batteries, frame, body, engine, inside, at the PCM box, etc as a matter of routine maintenance will kill most, if not all, of the 'Gremlins' that can cause these transient issues.

I am very aware of what the GM manual says - it's often right, and always a good source of information. However, it is also important to remember that a trip to the dealer for a little $5 problem like this often costs over $1000 by the time they discover all the things that their manual is wrong about, and you often come out of there with a whole bunch of new parts that had nothing to do with the original problem.

It was that way back in the 90's when these trucks were current and the techs were supposedly trained-up on them; nowadays, the techs have NO CLUE about the 6.5 and the electronic issues it has.

Something to keep in mind, friends.