Recent Forum Topics:

Google Translate:

Owners Forums for Ford and Volkswagen MPVs / SUVs

Ford Galaxy S-Max C-Max B-Max Tourneo Connect / Volkswagen Sharan Touran Tiguan Touareg Caravelle / SEAT Alhambra Alteca?

Mk1 and Mk2 VW Sharan Mk1 and Mk2 Ford Galaxy Mk1 and Mk2 SEAT AlhambraFord C-Max B-MaxVW Tiguan VW Touran Mk3 Ford GalaxyMk3 VW SharanMk3 SEAT AlhambraVW T4 T5 Caravelle TransporterFord Tourneo Connect VW Touareg

Author Topic: Ford Galaxy - Using VCDS/Vag-Com to Diagnose Faults with the PD Engine (Mk2)  (Read 12978 times)

Offline Mirez

  • Pondering the next mod...
  • Webmaster
  • Accredited Users
  • *
  • Posts: 3774
  • Thanked: 179
  • Model: Galaxy Mk2
  • Spec: 03 115PS Ghia
  • First Name: Mark
  • Region: South West
  • Country: United Kingdom
The diesel engine's fitted to the Galaxy are built by VW and known as a PD or Pump Deuce engine. Being a modern engine it is extensively monitored and controlled by an ECU and therefore can be interrogated by software to see faults and conditions.

The most popular software for this engine is Ross Tech's VAG-Com (Later renamed to VCDS) which is available in both lite (free) and pro (paid) versions. This guide give's an overview of how we can use this software to read the sensors in the engine, understand their readings and then diagnose a fault using the information.

Reading Fault Codes:

By far the easiest option to diagnosing a fault is simply to look at the fault codes the ECU has logged. It's important to remember that most local garages don't connect diagnostic equipment to the car as routine and very rarely do they reset any error codes that are logged. Since there is no date/time stamp on these codes, unless you know the memory was empty recently they should be cleared, the car driven, and then the memory  checked again to avoid red herrings!


You need to use the "Measuring Blocks" section of VCDS, select what blocks you want to log and then start the log running. When its finished you can open it up in Excel, select the columns you want and then convert that to a chart - the result is engine data in human ready form :)

Coolant Logging:  Coolant Temperature Sender Faults, Thermostat Fauls, Water Pump Faults, Booster Heater Faults

This is a simple log and chart from the coolant temperature sender from cold. Its worth checking this graph from time to time because the gauge on the dashboard  is not directly driven by the sender, instead its told its value by the instrument clusters electronics which are programmed to hold it at 90*c for any temperature from about 83*c to 96*c - Next time watch the gauge as it approaches 90*c you'll see it rising slowly until just before when it will suddenly just the extra to reach the indicated 90*c.

A good graph should rise reasonably smoothly and level off at 90*c (ish). Failure to rise or a long time to rise would indicate a stuck open thermostat, a non working booster heater and/or a faulty sender. Rising above 90 would indicate a thermostat stuck in the closed position, a faulty water pump and/or a faulty sender. Sporadic readings are nearly always a sender fault.

Example Graph:

The graph rises quickly, levels slightly around 70*c as the thermostat begins to open and cold water from the radiator is introduced and then continues to rise to around 85*c where is levels off.

Adding fuel temperature to the chart shows them rising nicely as expected, these two sensors are HEAVILY referenced by the ECU and if either are faulty there will be a big effect on fuelling, efficiency and performance.


Boost Leaks:

The pressurised air the turbo creates is known as Boost, leaking boost is bad for a number of reasons - firstly there will be a drop in performance. Secondly if the ECU thinks it has more air then it has it will overfuel resulting in lower MPG and higher oil temperatures and thirdly the turbo will have to work harder to maintain the level of required boost which will potentially shorten its life.

You should chart the values "Spec. intake press." (The amount of boost requested by the ECU) and "Actual intake press." (What the turbo is producing), the graph should look similar to this:


The values are close to each other with the actual lagging just slightly behind the specified. You can see in this example the car hasn't been used for some time and the VNT Vanes on the turbo are slightly sticky causing the actual boost to be a little higher on specified when the throttle in released.

MAF Sensor:

The MAF sensor sits right at the front of the intake, just after the air filter and measures the amount of air entering the engine. Failing or failed MAF's often don't log any error codes but the symptoms are nearly always low to very low of power and a lowered MPG.

Using VCDS to log both the MAF specified and actual, should result in a graph similar to this:


If you compare it to this graph of a bad MAF you can see just how the readings differ, notice the bad MAF never drops below around 450Mg/str. In this situation the ECU would be calculating its figures based on a much higher air flow rate so would be over fuelling the engine resulting in a lower MPG and poor combustion (less power)


« Last Edit: March 03, 2012, 09:47:46 am by Mirez »
03 Ford Galaxy 1.9 TDI 115 Ghia in Spruce Green Metallic
With cream leather interior, Full Bodykit, Remapped at 145bhp, Lowered on 18's
08 Ford Transit 2.2 TDI 115 in Frozen White
With retrofitted everything except another slidey door! :)

LAUNCH X431 Pad PRO - Scanning & Coding for all makes and models done in Wiltshire in exchange for winegums! :)


Related Topics

  Subject / Started by Replies Last Post
0 Replies
Last Post December 16, 2014, 09:28:00 pm
by jimmy-james
9 Replies
Last Post December 21, 2014, 01:12:30 pm
by bigdave982
12 Replies
Last Post May 22, 2015, 09:50:21 pm
by redbull2k
11 Replies
Last Post April 20, 2018, 08:18:59 pm
by Daza101
141 Replies
Last Post September 15, 2016, 02:49:32 pm
by fordnewbie
2 Replies
Last Post May 05, 2021, 08:29:58 pm
by ginettaman