Thread: Gap IID tool and fault messages

Originally Posted by rdenyer

Hello fellow Discovery drivers,
I have finally made the decision to purchase the Gap IID tool BT version.
It arrived and I have been able to complete a few simple tasks, like setting a new ride height, read error codes etc.
I have two simple questions
1. Is there anywhere where other Gap IID tool owners have document cool things that can done?
2. Is there anywhere /anyone that can help with fault codes ? some are pretty obvious, like this "B1C79-14 (2E) Front washer pump relay output circuit - General electrical failure" , and yes my washer wiper pump is not working, but I have others like "U0122-87 (28) Lost communication with vehicle dynamics control module - Bus signal/message failure - missing a message( at 126276 km )" for which I have no idea where to start looking.



Regards,
Richard

I have a service manual that has diagnostic codes. Literally hundreds of them. Here's the detail for the second one. Usually, what most people do is clear the codes and see if they return. If they do, then look further. If not, then it's probably OK. Wiser heads may comment further.

U0122-
87

Description

Lost Communication
With Vehicle
Dynamics Control
Module - Missing
message


Possible Causes

Anti-lock brake
system control
module power or
ground circuit open
circuit, high
resistance
High speed CAN
bus circuit short
circuit to ground,
short circuit to
power, open circuit,
high resistance
Anti-lock brake
system fault


Action

Refer to the electrical circuit diagrams and check
the anti-lock brake system control module power
and ground circuits for open circuit, high
resistance
Using the manufacturer approved diagnostic
system, perform a CAN network integrity test.
Refer to the electrical circuit diagrams and check
the high speed CAN bus circuit for short circuit to
ground, short circuit to power, open circuit, high
resistance
Using the manufacturer approved diagnostic
system, check the anti-lock brake system control
module for related DTCs and refer to the
relevant DTC index


HTH,
Martin

It is not unusual to get lost communication errors, just clear it and if it is recurring error you may have a problem. Obviously if the washer doesn't work and there is an error there is a problem.

I always have a continual error regarding lost communication between the parking system and the audio system, yet the two still work fine together so I ignore it. It's not the sort of error that causes a check engine or any other light, so if it wasn't for the IID I'd be none the wiser.

Originally Posted by DiscoJeffster

I always have a continual error regarding lost communication between the parking system and the audio system, yet the two still work fine together so I ignore it. It's not the sort of error that causes a check engine or any other light, so if it wasn't for the IID I'd be none the wiser.

I get the same error - Suspect it is a feature of the 2010 3.0 TDV6 models... :P

My understanding from the LR trained UK mechanic who looked after my D3 is that in general you can ignore any 'U' codes in the first instance. They are often modules taking action and issuing a code in response to some other primary fault. For example, the engine may have a true fuel pump error and issue a 'P' code on the CANBUS, which will result in the engine the lowering power output and issuing 'U' code, and the transmission then limiting available gears and issuing a 'U' code, and the suspension then limiting height changes and issuing a 'U' code. The original 'P' code fault is where to start looking.

But then I'm an engineer and not a mechanic

Andrew

Originally Posted by rdenyer

...some are pretty obvious, like this "B1C79-14 (2E) Front washer pump relay output circuit - General electrical failure" , and yes my washer wiper pump is not working.

Obvious, so you say. I'm getting errors for both the front and rear circuits. This makes sense since a single pump is used for both the windshield and rear window. However, the fuse is never blown and 3 new pumps in a row have died within a couple of days to a couple of weeks. Did you ever resolve your fault? The error is for a relay, but I'm not sure where this relay is located. When I press the wiper button I can hear clicking in the middle of the dashboard, but I don't want to tear things apart until I know if there is a relay there. Does anyone have any ideas? This is the only place on the Internet I can even find mention of these faults!