Eurovan Full Camper, Short to ground faults

The Problem……..

vw_logoAny guidance would be much appreciated… Thanks! I took it in to a VW shop and they said they were able to fix it due to 2 wires that were disconnected from Fuse/Relay area (related to Secondary Air something) 1 Week later the codes are back, but I see no wires disconnected…

VAG-COM Version: Release 404.0-US

Control Module Part Number: 022 906 032 AF
Component and/or Version: MOTRONIC ME7.1 G 0003
Software Coding: 00003
Work Shop Code: WSC 02743
9 Faults Found:
17833 – EVAP Purge Valve (N80): Short to Ground
P1425 – 35-00 – –
17880 – EVAP Leak Detection Pump: Short Circuit to Ground
P1472 – 35-00 – –
17843 – Secondary Air Pump Relay (J299): Short to Ground
P1435 – 35-00 – –
17829 – Secondary Air Injection Solenoid Valve (N112): Short to Ground
P1421 – 35-00 – –
17923 – Intake Manifold Valve (N156): Short to Ground
P1515 – 35-00 – –
17525 – Oxygen (Lambda) Sensor Heating Circuit: B1 S2: Short to Ground
P1117 – 35-00 – –
17876 – EVAP Canister Solenoid Valve 2 (N115): Short to Ground
P1468 – 35-00 – –
16486 – Mass Air Flow Sensor (G70): Signal too Low
P0102 – 35-00 – –
17523 – Oxygen (Lambda) Sensor Heating Circuit: B1 S1: Short to Ground
P1115 – 35-00 – –

The Fix…………………………..

The good news is that VAG-COM practically “diagnosed” the problem for you, and it is likely to be a cheap fix if you DIY. Bad news is that the problem could be intermittent, and you will probably need to do some careful inspection of portions of the wiring harness to find evidence of physical damage, or determine if there was a “tap” made into the harness for some aftermarket device, which may have been removed.

A wiring diagram will really help. Maybe someone can post page 8/10 on the ECM section.

The problem is on or related to a +12 V supply that is common to all of the components that faulted. It is called E30, and goes through connector 87a. The 87a connector is in the engine compartment, but I didn’t locate it yet.

First, a quick check. The full campers tend to have a lot of aftermarket stuff added, long after Winnebago did their mods, sometimes by a RV dealer.

1. Check fuse S117. It is on a small fuse holder attached below the main fuse/relay panel located behind the dash over the driver left knee area. It’s supposed to be a 15A fuse, beware of substitutions. Very obvious will be the two red with blue stripe wires going to it.
While you are there, look for taps that were added for sound system, DVD, alarm, whatever. Do not tap power from ANY red with blue stripe wire under the panel or in the engine compartment, as all of the emissions equipment runs off this supply, and voltages are monitored by the ECM to sense faults. Even a radio substitution can cause problems unless the harness was correctly modified. (search K+ wire and stereo head unit topics)

2. Remove the covers from the top and bottom of the engine and the vehicle battery areas. Find the Mass Air Flow sensor on the intake tube between the air cleaner and throttle body. It has the red with blue stripe wire going to its connector. Follow its wires to the bundle right behind the engine that is covered with a silver fabric heat shield. The wires for the O2 sensors will also emerge from this area. Basically you must check wiring related to this bundle for physical damage. You will need to follow the wires down the exhaust manifold to the oxygen sensors, too. A positive to ground short or intermittent leak can be hard to find, even with a meter and diagram.

3. The E30 wires go through connector 87a, I think it is somewhere low in the engine compartment and on the driver’s side. Check the connector, but don’t force it open and bust it. Volkswagen/Audi use connectors that are non-intuitive to open and sometimes need special tools to avoid damage.

Also look for screws used to mount aftermarket stuff from the driver area forward. Sheet metal screws are a great way to puncture or crimp wires, causing shorts that can take years to show up.