Diagnostics – Pulling the Codes

You can display the codes by inserting a fuse in the top of the fuel pump relay. The Fuel Pump relay is located under the hood in the main fuse panel near the windshield on the drivers side.

If the vehicle starts and runs: You should drive the car for a minimum of 5-10 minutes and raise the engine speed above 3000 RPM and ensure that the manifold pressure goes above 1.2 bar. You want the engine coolant temp to get above 80C, (176F). You should accelerate at full throttle in 3rd gear to exercise this diagnostic system correctly.

The "Check Engine" warning light should come on whenever the fuse is inserted into the top of the fuel pump relay.

UNDER NORMAL DRIVING CONDITIONS THERE SHOULD NOT BE A FUSE INSERTED ON TOP OF THE FUEL PUMP RELAY.

THIS FUSE IS ONLY INSERTED "TEMPORARILY" INTO THE TOP OF THE FUEL PUMP RELAY TO ACTIVATE THE FAULT CODES OR TO RUN THE OUTPUT TESTS. There should not be a fuse "permanently" installed in these contacts on top of the fuel pump relay.

NOTE:The fault code reading procedure will be canceled if the engine RPM is raised above 2000 or if the ignition is turned off.

Each fault code consists of four groups of pulses.

The exact sequence for each code is a start sequence of 2.5 seconds with the lamp on, and 2.5 seconds pause with it off.

The codes then follow as a half-second pulse with the light on, separated by a half-second pause with the light off, with a larger pause of 2.5 seconds between each set of pulses.

Example: If no fault codes are stored, code 4444 will be displayed by the ECU. The ECU will turn the "Check Engine" light on and off as follows after the fuse is inserted into the fuel pump relay for 4 seconds and then removed.

Light on (2.5 sec), Light off (2.5 sec)
Now here comes the code 4444
Blink, pause, Blink, pause, Blink, pause, Blink, (2.5 second pause)
Blink, pause, Blink, pause, Blink, pause, Blink, (2.5 second pause)
Blink, pause, Blink, pause, Blink, pause, Blink, (2.5 second pause)
Blink, pause, Blink, pause, Blink, pause, Blink, (2.5 second pause)


NO START CONDITION: Crank the engine with the starter for at least 5 seconds and make sure you leave the ignition on after cranking the engine during the no start condition.

NOTE: On the 1986-88 5000T/Q and early 1989 200T/Q, the ignition should not be turned off after doing this full throttle test road test or after the "No Start" cranking test is done, as the fault memory will be erased.

After doing the road test or the "No Start" cranking test, proceed to the section below for reading any fault codes stored during this process.
Here is a list of fault codes:
ECU Fault Code Listing 10V Turbo Engines
1986-88 5000 Turbo and 5000 Turbo Quattro,
1989-91 200 Turbo and 1989-90 200 Turbo Quattro,
UK ur-quattro with MB Engine
NOTE: The fault codes shown below indicate that the ECU has recorded a problem with one or more of the following:

A system component, the wiring, the wiring connections, or from a engine mechanical problem (vacuum leak, low compression, etc.).

If you get multiple fault codes recorded, step through the fault code reading sequence and write down all the fault codes that were recorded. After you locate the source of the problem for the "first" fault code you read, you may want to then clear all the fault codes stored and drive the car again to see if the other fault codes are stored again. In some cases multiple fault codes are recorded even though there may be only one problem with the system.

Code Number
Source of Fault code
Possible cause
Recommended Check or Repair
Symptom in some cases
•1111 (Blink Fault Code), VAG1551/2 Fault Code Number 65535
Engine Control Unit (ECU)
Defective memory circuits
Replace ECU

•2111 (Blink Fault Code), VAG1551/2 Fault Code Number 00513
RPM sensor
Open or short circuit,
Defective sensor & cables, metal fragments on flywheel teeth

•2112 (Blink Fault Code), VAG1551/2 Fault Code Number 00514
Timing (62 degrees BTDC) reference sensor
Flywheel pin damaged/missing,
Mis-located Sensor, flywheel pin, distributor hall sensor out of adjustment

•2113 (Blink Fault Code), VAG1551/2 Fault Code Number 00515
Hall sender in distributor
Distributor alignment, faulty sender,
Mis-located sensor & distributor

•2121 (Blink Fault Code), VAG1551/2 Fault Code Number 00516
Idle switch inside Throttle switch
Switch open ckt, stuck closed
Switch defective (Internal solder connections intermittent) or wiring problem

•2123 (Blink Fault Code) , VAG1551/2 Fault Code Number 00517
Full load switch inside Throttle switch
Switch open ckt, stuck closed
Switch defective (Internal solder connections intermittent) or wiring problem

•2141 (Blink Fault Code), VAG1551/2 Fault Code Number 00535
Knock regulator #1
Excessive knock, timing is being retarded by maximum amount 7.8 degrees, Low boost on 20V,
Fuel octane too low, Excessive Compression, excessive boost

•2142 (Blink Fault Code), VAG1551/2 Fault Code Number 00524
Knock sensor #1
Open or short circuit, Defective sensor
Check sensor and wiring
Symptom: Timing retarded, High fuel consumption, power loss, Boost pressure not attained

•2143 (Blink Fault Code), VAG1551/2 Fault Code Number 00536
Knock sensor #2, (Cylinders 3, 4, 5)
1989-91 200TQ, 1989-91 200T, with dual knock sensor MC engine,
Excessive knock, timing is being retarded by maximum amount 7.8 degrees.
Fuel octane too low, Excessive Compression, excessive boost


•2144 (Blink Fault Code), VAG1551/2 Fault Code Number 00540
Knock Sensor #2, (Cylinders 3, 4, 5)
1989-91 200TQ, 1989-91 200T, with dual knock sensor MC engine,
Open or short circuit,
Defective sensor or wiring
Symptom: Timing retarded, High fuel consumption, power loss, Boost pressure not attained

•2214 (Blink Fault Code), VAG1551/2 Fault Code Number 00543
Engine Over-revved
(1989-91 200TQ, 1989-91 200T),
also UK MB engine.
Engine has exceeded rev limit (~6700-6900 on MC engine
Driver has heavy right foot.

•2221 (Blink Fault Code), VAG1551/2 Fault Code Number 00575
Manifold Pressure too low, too high, control difference.
Vacuum hose to ECU pressure sensor
Vacuum hose missing or leaking,
Check hose
Symptom: Loss of Power

•2222 (Blink Fault Code), VAG1551/2 Fault Code Number 00519
Pressure sensor
ECU Pressure sensor defective,
Repair or replace ECU

•2224 (Blink Fault Code), VAG1551/2 Fault Code Number 00544
Over boost condition (1989-91 200TQ, 1989-91 200T)
UK MB engine.
Boost pressure exceeded 1.6 bar for MC, 1.8 bar for MB
Waste gate or pressure hose, Waste Gate Solenoid/hose problem

•2312 (Blink Fault Code), VAG1551/2 Fault Code Number 00522
Coolant sensor
Open or short circuit,
Defective sensor or wiring
Symptom: Cold starting difficulties at low temperatures, Poor idle and acceleration during warm up

•2322 (Blink Fault Code), VAG1551/2 Fault Code Number 00523
Inlet air temp
Open or short circuit
Defective sensor or wiring
Symptom: Slight power loss, Increase in fuel consumption

•2342 (Blink Fault Code), VAG1551/2 Fault Code Number 00523
Oxygen Sensor
Sensor Wiring or Sensor defective
Symptom: Emissions not within specifications

•4444 (Blink Fault Code), VAG1551/2 Fault Code Number 00000
No Faults have been recorded.

•0000 (Blink Fault Code), VAG1551/2 Fault Code Number 00000
End of Diagnostic Output