Truck not running correctly - Diesel Forum

dgorczyca · 07-28-2010, 02:31 PM

Okay guys, I am just about at my wits end. I have been researching on this awesome site for several weeks now, but I am stuck. I recently put in a new IDM, glow plug relay, UVCH on drivers side, 4 glow plugs on drivers side, icp sensor, ipr, cps, changed fuel filter, changed engine oil and filter. All this was done for several codes I got when the truck just stopped running one day while driving.

So I started it yesterday and it started right up. Ran for about 10 minutes then died. I got the following codes: P0472, P1210, and B1483.

When the ICP is connected the truck takes 3-6 tries to get it started up again after I turn it off. Any suggestions would be much appreciated.

Dave

klhansen · 07-28-2010, 03:36 PM

P0472 Exhaust Back Pressure Sensor Circuit Low Input

Possible causes:
open EBP sensor circuit
biased sensor/PCM
short to SIGN RTN or PWR GND on EBP sensor circuit
open in VREF circuit

P1210 Injection Control Pressure above expected level
Possible causes:
biased ICP sensor
open ICP signal return
signal circuit shorted to power
damaged PCM

Notice a common thread here? The 3-wire sensors (EPB, ICP and others) share a common VREF circuit, and also Signal Return.

That second code is probably the cause of your problems. It may be a bad ICP sensor or a short somewhere in the sensor harnesses. One guy reported that a bad EBP sensor killed his truck, it would run without it plugged in, but didn't when the EBP was plugged in.

You said that it took multiple tries to start with the ICP plugged in. That indicates a problem with the ICP sensor. If it will start and run well with the ICP unplugged, then the culprit is most likely your ICP sensor.

The B1483 is a GEM code and not critical to the engine running. Brake Pedal Input Circuit Failure
Could be a bad brake pedal position switch.

dgorczyca · 07-28-2010, 05:16 PM

Thank you very much! If the sensor or PCM is biased, what are my options?

I also forget to mention that the truck sounds different. Not as loud as it was prior to all these issues. Would a bad icp cause this?

Thanks

klhansen · 07-28-2010, 08:09 PM

If you have a biased ICP sensor that's telling the PCM that the HP oil pressure is higher than ~500 psi at idle, even though the pressure is actually lower, the PCM will send a signal to the IPR to bleed off some pressure. If it gets low enough, the engine won't run right because the spray pattern will be too coarse and won't burn right.

And yes, abnormally low HP oil pressure will make the engine quieter.

Try pulling the ICP connector and see if it acts closer to what you had before. Disconnecting the ICP makes the PCM use default values to control the HP oil pressure. If it runs better, your ICP sensor is suspect.

Dauntless · 07-28-2010, 11:33 PM

On this same line, could an ICP sensor go bad and not throw any codes? I am having similar issues with mine, haven't tried starting it with the ICP disconnected but disconnect it while running, just turns on the SES light.

dgorczyca · 07-29-2010, 06:33 AM

Thanks for the great information. I have also printed out some testing information for the ICP sensor and wiring and it gives me pin numbers and circuit numbers. This is great, but how do I locate them. I have a repair manual, but it does not give me the information I am looking for. I need to find pin numbers 91, 87, and 90. They are located in circuits 359, 812, and 351. I am assuming I need to buy a more in depth repair manual?

Please help me out.

Dave

woodnthings8 · 07-29-2010, 10:25 AM

Those pins are located on the PCM connection. It is a 104 pin connector that it mounted to the PCM just below the Brake Master Cylinder on the firewall. You will need to unscrew the 10mm bolt to disconnect it (NO KEYS IN THE IGNITION).

This is where a breakout box comes in handy, You install it between the connector and the PCM and you can just use your meter to check it while it is running.

Here is the layout of the connector.

dgorczyca · 07-29-2010, 07:16 PM

Thanks for the great info! Where can I get a breakout box?

woodnthings8 · 07-29-2010, 08:48 PM

I got mine off of ebay. Lots of dealers were going out of business and they have been sold on ebay for around $150.

dgorczyca · 07-29-2010, 08:56 PM

Wow! That's a great deal. I just looked some up, they sure aren't cheap.

On another note, I ran the KOER test on my Autoenginuity and it stalled out the truck. This can't be good? I also figured out that I am not getting the 5 volts on the ICP plug.

woodnthings8 · 07-29-2010, 09:19 PM

Check continuity on pin 21 of the connector mounted to the drivers side valve cover. That is the VREF 5 Volt signal to the ICP, Oil Temp, EBP, and ACT Sensors.

I 'm thinking if you have VREF to those, you may have a break in the wire somewhere on the engine.

dgorczyca · 07-30-2010, 06:24 PM

Okay, so I tested pin 19 on the 42 pin connector with the key turned on. There is no voltage coming from the PCM. Does this mean the PCM is junk?

klhansen · 08-01-2010, 01:18 AM

Quote:

Originally Posted by dgorczyca

Okay, so I tested pin 19 on the 42 pin connector with the key turned on. There is no voltage coming from the PCM. Does this mean the PCM is junk?

Not necessarily. It could stil be a wiring issue. Those can be a PITA to find. If you have a buddy with a very similar truck (preferrably same PCM code), you could try swapping PCM's. If the problem goes away with his PCM in your truck, then it's your PCM, if it doesn't , then you'll have to track down the wiring issue.

woodnthings8 · 08-01-2010, 10:55 AM

Try pin 21 on the 41 pin connector which is circuit 351, this is the Reference Voltage from the PCM. After looking at the PCM connector diagram 19 is signal return, and 21 if VREF. On the PCM connector it is pin 90 for VREF.

If you still show no voltage you can take a continuity reading between the 41 pin connector and the PCM connector. This will tell you if the wiring is ok or not. Circuit 351.

Also check the wires at the 41 pin connector on the Valve Cover. They tend to lay on the cover and chafe through on the bottom.

dgorczyca · 08-01-2010, 02:19 PM

Thanks for the replies. I already repaired a few wires on the 42 Pin harness that were worn from rubbing on the valve cover. I will do some more testing and post my results. The truck has been running okay since I disconnected the ICP Sensor. I also hooked up my autoenginuity and I still get code 1210, but now I have code 1280. Any ideas why?

Thanks,
Dave