I have a '02 PSD F-250 CA, approx 270kmi. and a SuperChips controller that I did not install, but has been on the truck for +130kmi. I have a couple issues and need some help. I have done the obligatory search, but can't find anything that quite fits the bill.
First, I have obd codes p-0670 thru p-0678. I know these are GPCM and all the individual plugs, but I'm not sure if the GPCM is likely to kill them ALL at the same time when it goes, or if it is another problem. The "Wait to Start" light comes on, and will stay on longer when the truck is cold than when hot.
Next, code p-0470, exhaust backpressure sensor. Seems to be pretty self explanitory, but I just wanted to be sure its just one of the multi-prong sensors after the turbo and see if anyone can help me ID which one.
Lastly, (and this one is freaky) twice recently after I pressure wash my engine compartment while the engine has been both hot and cold, when I attempt to start the truck it begins to turn over and then a brief grinding (kinda like a high speed version of the starter click when a battery is dead) then NOTHING....for about 20min. Then, like nothing happened, it fires right up.

So, in review, I got issues....and my truck is only one of them. Thanks

 

WOOO HOO! 2 posts!

 

Welcome to FTE.

Here are the descriptions of the codes that you pulled.

P0070 Ambient Air Temperature Sensor Circuit
P0071 Ambient Air Temperature Sensor Range/Performance
P0072 Ambient Air Temperature Sensor Circuit Low Input
P0073 Ambient Air Temperature Sensor Circuit High Input
P0074 Ambient Air Temperature Sensor Circuit Intermittent
P0075 Intake Valve Control Circuit (bank1)
P0076 Intake Valve Control Circuit Low (bank1)
P0077 Intake Valve Control Circuit High (bank1)
P0078 Exhaust Valve Control Circuit (bank1)

Here is a link to clean the EBS:

Welcome to guzzle's Exhaust Backpressure Sensor Cleaning Maintenance Web Page


You may have problems when pressure washing your engine due to the electronics getting wet. Most here use simple green and a hose on low pressure. covering up the vitals with plastic bags.

 

First off, welcome to FTE. Next, stop powerwashing your engine. There are too many electrical components and o-rings that don't react well to high pressure water. You might start seeing some corrosion issues from water being forced into places where it's not supposed to be, and those are a pain to track down. Use some simple green, or your favorite detergent and low pressure water to clean the engine (cold or warm but not hot)

As for the GPCM codes, it kind of sounds like the GPCM itself is acting up, not the individual glow plugs, unless they've failed one at a time in the past. The light in the dash isn't really tied to the glow plugs, it's simply a reminder powered by the PCM. It will stay on longer or go off quicker based on sensor readings like EOT, BARO, etc. You might want to figure this one out before the weather gets too cold. You could either start ohming some of the wires, or replace the GPCM if it isn't too expensive. Sorry, I don't know what those cost.

The P0470 code is fairly common with tuners, but most find they need to clean the tube connected to the sensor. Here's a link showing how to do it. Welcome to guzzle's Exhaust Backpressure Sensor Cleaning Maintenance Web Page The EBP sensor is in front of the motor just behind the serpentine belt.

 

Thanks. They seem to run about $225 and plugs are about $100 so its not a killer, but still something I'd rather not have to pay for. Any chance you could direct me to so some testing procedures?

 

https://www.ford-trucks.com/forums/5...elay-test.html

 

Oops, that was the GPR test. Here is a procedure from
03-21-36***ENGINE - 7.3L DIESEL - GLOW PLUG CONTROL MODULE - VEHICLES WITH CALIFORNIA EMISSIONS - SERVICE TIP


DIAGNOSTIC PROCEDURE

The GPCM supplies power to the glow plugs through solid state drivers and performs diagnostics internally to detect and report system failures. The Powertrain Control Module (PCM) still controls glow plug on-time through a control circuit between the two modules. On-time is a function of engine oil temperature, barometric pressure, and battery voltage. This is the same as the previous system.

There are two circuits connecting the PCM and the GPCM. PCM Pin 101 is still used as the control circuit which activates the GPCM to enable glow plugs. PCM Pin 8 is used as the serial communication circuit which is used for the GPCM to report failures to the PCM. The PCM monitors these circuits for failures. The GPCM internally performs diagnostics for individual glow plug/glow plug circuit failures. When a failure is detected, the GPCM will transmit that failure to the PCM over the communication circuit. If a fault is detected, it will be stored in PCM continuous memory. New fault codes have been added and descriptions are as follows:

P0670 - Glow plug (GP) control circuit malfunction
P0671 - Glow plug #1 circuit failure (circuit/GP)
P0672 - Glow plug #2 circuit failure (circuit/GP)
P0673 - Glow plug #3 circuit failure (circuit/GP)
P0674 - Glow plug #4 circuit failure (circuit/GP)
P0675 - Glow plug #5 circuit failure (circuit/GP)
P0676 - Glow plug #6 circuit failure (circuit/GP)
P0677 - Glow plug #7 circuit failure (circuit/GP)
P0678 - Glow plug #8 circuit failure (circuit/GP)
P0683 - Glow plug diagnostic signal communication fault
When servicing this system for fault codes, carefully inspect all connections for damaged or pushed out pins and fully engaged connectors. The green engine harness connector must be connected to the green glow plug monitor connector and the black engine harness connector must be connected to the black glow plug monitor connector. After any repair or removal of the GPCM components, it is very important to re-run the KOER Glow Plug Monitor self test to verify no system faults are present before releasing the vehicle. For diagnostic procedures, refer to the new pinpoint test for the GPCM system (Figures 1-6).

NOTE: WHEN SERVICING OR DIAGNOSING THE GLOW PLUG SYSTEM OR WHEN DISCONNECTING THE GREEN AND BLACK CONNECTORS ON THE GPCM, UNBOLT THE MODULE FROM THE MOUNTING BRACKET FIRST AND THEN DISCONNECT THE GPCM GREEN AND BLACK CONNECTORS. THIS WILL ALLOW FOR EASIER DISCONNECT AND WILL HELP PREVENT DAMAGE TO THE CONNECTOR TERMINALS DURING DISASSEMBLY/ASSEMBLY.




OTHER APPLICABLE ARTICLES:

 

Pin 3 is the battery input, and Pin 9 is VPRW input. To test the GPCM the manual calls for unplugging the EOT (engine oil temperature) sensor to maximize glow plug on time, the checking voltage between test pin 101 and ground as soon as the key is turned on. Low voltage (1 or less) for the first minute or two while the glow plugs are on, followed by 10+ volts after the glowplugs cycle off indicate a bad GPCM.

You can check the glow plugs using an ohm meter using the diagram above. Place one lead on 1 of the glow plug pins and the other lead on the negative battery post and you should see an ohm reading between 0.2 and 2 ohms. 1 ohm is considered a good glow plug, over 5 ohms means you need to change that plug.

You can also check for continuity between the GPCM plug and the valve cover plug. Typical resistance here should be less than 1 ohm.