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Discussion Starter #1 (Edited)
U1208 ESP No communication with engine ecu

So I've had this U1208 fault code for ages but I can't seem to get to the bottom of it.
When I check the ABS values and graphs in Diagbox everything seems fine. Voltage is ~14.4v, speed sensors are fine, brake pressure and lights, steering wheel angle sensor etc.. everything seems perfect. But still I get the "U1208 No communication with engine ecu" immediately after I start the car, or as soon as I clear the fault code with the car started.

When I run the actuator tests I can hear the abs block humming, but a few of the valves don't seem to be clicking. Recirculation pump runs fine.

I never get any STOP codes or any ABS codes (unless I unplug the abs block connection :eek:) so I'm thinking the ABS itself is ok.

I'm not sure what Diagbox is looking for from the engine ECU, torque or engine speed is all I can think of. Everything else (steering wheel sensor, gyro values, etc) seems to go straight to the ABS ECU. If the solenoid valves were the problem wouldn't I be getting ABS errors and STOP lights?

I'm assuming the CAN network is fine too since there's at least some communication going on with the engine ecu (engine speed, torque etc), but I'm not an expert by any means..

Powers and grounds to the ABS ECU are good. Took the ECU off the hydraulic block and the circuit board looks fine, no obvious burns or water damage etc, but a few of the solenoids on the block had a few small blobs of oil on the top of them, just like a tiny dot on the top of one or two of them. Not sure if it's normal or not but I can't see why it would be an issue.

Cruise control works fine too so I'm assuming that rules out a bunch of stuff, like the brake switch, etc.

Can anyone shed some light on this? Any other diagnostic paths I can take before I go away and buy a new ABS block?
 

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I think the solenoids idea is a red herring for you, oil won't affect solenoids I've seen then work totally submerged on industrial hydraulic power packs.

BBA Reman suggest that P12** faults are fuel and air metering issues but don't specifically list P1208 unfortunately.

Have a good Google around ...........

Another site suggests ... " P1208 Peugeot ... the main thing to check is to verify the operation of the VCT solenoid. You're looking for a sticking or stuck VCt solenoid valve caused by contamination...... The leak detection pump is part of the evaporative emissions system. This system tests the fuel system to make sure it is not leaking fuel vapors into the air. The system pulls a vacuum on the fuel system and holds it for a period of time.

Sorry I cannot help more.
 

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Discussion Starter #3
I think the solenoids idea is a red herring for you, oil won't affect solenoids I've seen then work totally submerged on industrial hydraulic power packs.

BBA Reman suggest that P12** faults are fuel and air metering issues but don't specifically list P1208 unfortunately.

Have a good Google around ...........

Another site suggests ... " P1208 Peugeot ... the main thing to check is to verify the operation of the VCT solenoid. You're looking for a sticking or stuck VCt solenoid valve caused by contamination...... The leak detection pump is part of the evaporative emissions system. This system tests the fuel system to make sure it is not leaking fuel vapors into the air. The system pulls a vacuum on the fuel system and holds it for a period of time.

Sorry I cannot help more.
Nice one for the reply.

I'm an idiot! The code is U1208. I had the P stuck in my head from a P1471 error on my butterfly solenoid valve (which is fixed now).

I didn't think the oil on the solenoids was an issue but thought I'd mention it anyway since I'm a bit of a newbie to auto electrics and mechanics.

I've done loads of Googling but haven't come across any solutions that match. Some people with faulty ABS sensors mainly. The car is a diesel so I don't think it has an EVAP system anyway. I haven't come across any VCT solenoid in my searches either. Been scanning the diagrams on Servicebox a lot. I think I read somewhere that sometimes the EGR can cause ESP issues but I think the previous owner had it blocked off.

 
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