Search our website

Hints and Tips: Volkswagon Idle Speed Problems

Increased idle speed, fault code 533
Cause: 
Clashing endurance in changes of idle speed. Caused by using the accelerator at the exact same 
time as starting the engine.
Models affected: 
Golf, Passat, Polo Classic
Service: 
Follow instructions for starting the vehicle as mentioned in owner's manual. If there is no success 
control units of the engine should be replaced:
Golf Part No. 037 906 025 T
Passat Part No. 037 906 025 AA
Polo Classic Part No. 6K0 906 025 E 

Some faults when running
Cause: 
Problems in the carburation assemblages can be due to contacts that have loosened, the capacity 
to withstand modulation and inadequate earth linkings usually caused by cleaning the engine too 
assertively and also having uncovered cable connectors. 
Service: 
If need be before assembling, clean all plugs and contacts with spirit After spraying ensure parts 
are dry.

Constantly changing, immoderate idle speed - engine commences only after charging the battery.
Cause: 
If the battery is discharged or disconnected the Motronic control units lose their basic set up regulations.
Service:
If the battery was discharged or disconnected, turn on the engine for about 10 seconds and then switch 
off. This will clear the system and reset it. The engine should start straight away with no recurrence of 
previous problems. 

Erratic idle speed - igntion timing fluctates 
Cause: 
Due to a weak union between the rotor and ignition distributor shaft, the rotor can become loose and 
can coil around on the distributor shaft.
Models affected: 
Mono Motronic 1.8 l 55/66 kW with Valeo or Sagem ignition distributor 050 905 205 AL Golf, Passat
Service: 
Take off the distributor cap, distributor fingers and protective caps. Investigate the arm of the rotor to 
make sure it has been installed properly.
If the rotor arm is loose, attach the ignition distributor - Part No.050 905 205 AH. As the replacement 
parts are supplied by a different supplier using a different make up, the fault does not affect them.

Poor idle speed, engine jerks regularly
Models affected:
Magneti Marelli 1AV, AEE engine
Cause: 
The Multipoint engine in the Golf has been made more protective to the environment by keeping the 
idle speed very low (600-700 rpm). Therefore the idle speed is more noticeable in comparison to the 
last model. 
Fixing must be avoided. The idle speed cannot run smoothly and cannot be changed. Discussion 
on this is on going. 

Vehicle plays up when driving away and stops movement
Cause: 
The Multipoint engine in the Golf has been made more protective to the environment by keeping the 
idle speed very low (600-700 rpm). Therefore there will be some hardship when driving away from idle 
speed in comparison to the last model. The engine speed must be increased using the accelerator 
and the throttle valve control unit either alternatively or at the same time.
Models affected:
Magneti Marelli 1AV, AEE engine
Service: 
Fixing must be avoided. The idle speed cannot run smoothly and cannot be changed. Discussion on 
this is on going. 

VR6 engine shakes at idle speed - The front seats vibrates uncomfortably
Cause: 
Discordant burning due to too much residual fuel or air in the combustion chamber. 
Service: 
Investigate the fuel injection and ignition system as advised in the workshop manual to eliminate 
faults in this area. 
Untighten the engine mountings, start the engine for a tension-free position and then tighten the mountings. 
Put in place twin earth spark plugs - Part No. 101 000 035 AB/AA. 

Increased idle speed (max. 2,500 rpm) after starting the engine with a coolant temperature between 18yC 
and 29.5yC 
Model year 96
Magneti Marelli 1AV; 1.6 l; AEE engine
Cause: 
Program faults lead to an idle speed increase (max. 2,500 rpm) after turning the engine with a coolant 
temperature between 18yC + 29.5yC. Approximately 40 seconds later or once the acceleration is used 
(the throttle valve angle changed by less than 5y) then normality returns to the idle speed.
Service: 
Connect the control unit that has been modified
Polo - Part No. 032 906 030 E
Polo Automatic - Part No. 032 906 030 H
Golf - Part No. 032 906 030 K 
The control unit must be adjusted to the electronic immobiliser. Prepare a basic setting of the engine 
control unit (adjusting it to the throttle valve control unit).

After ignition the engine only runs with 500 rpm and has no response from the accelerator. 
Cause: 
As the start was too short and the engine was too low, the idle speed stays at around 500 rpm 
(approx. 50°C coolant temperature).
Service: 
Switch off the engine and immediately turn it back on. To stop this happening again, the starter motor 
must keep going for at least a couple of seconds. If it doesn't the control unit will not acquire the correct 
information and will be faulty as above. DO NOT ATTEMPT TO FIX IT.

Engine fails to ignite at idle speed, runs irregularly and doesn't have a good response from the accelerator. 
There is a break in the ignition transformer. 
Cause: 
Final transistor point in the ignition transformer is in risk from voltage, particularly when temperatures are low.
Service: 
Investigate ignition transformer housing for breaks '1' and inflations '2. In order to achieve this, take away the 
ignition transformer.

Idle speed varies irregularly scattered between 500 and 800 rpm
Cause: 
The cable of the accelerator is fastened too firmly, and so the idle switch is not functioning very well when used.
The fault memory of the engine control unit can show the fault "idle switch F60" or "sender for throttle valve 
positioner" (but cannot be relied to do so). 
Models affected: 
Polo
Service: 
Adapt the accelerator cable and take away the fault memory

When using the power steering (engine switches off or the idle descends abruptly when turning the steering 
wheel fully)
Cause: 
Without the pressure switch F88 the power steering hose is adapted. 
Models affected:
Polo
Service: 
The power steering hose must be investigated as to whether it is attached with the pressure switch F88. 
If the steering hose isn't attached, adjust the power steering hose with the pressure switch F88 and add a 2 pin 
connector under the battery mounting. The subsequent hoses must be employed: LHD: Without air 
conditioning: Part No. 6N1 422 893 D With air conditioning: Part No. 6N1 422 893 
ERHD: Without air conditioning: Part No. 6N2 422 893 DWith air conditioning: Part No. 6N2 422 893 E 

Increased idle speed occurring at intervals up to 3,000 rpm.
Cause: 
Incorrect residual volume adjustment on the injection pump.
Models affected: 
Polo
Service: 
Investigate the throttle cable and injection pump for freedom of actions.
Study carefully the residual volume adjustment:
Make the engine warm (coolant temperature > 80 °C).
Insert a 5 mm spacer between stop screw "2" and adjustment lever "3" (ensure that the spacer is untwisted).
After untightening the clamp nut turn the stop screw "2" (clockwise) until the idle speed stays the same.
Get rid of the spacer.
Look at the idle speed and if you need to set the idle speed adjustment screw "1" to 940 ñ 20 rpm.
Fit again the 5 mm spacer.
If the set value is exceeded by the idle speed, the "2" stop screw must be twisted so that it reaches the original idle speed.
If the idle speed doesn't reach this point, twist the "2" stop screw, until there is an increase from the idle speed.
Take away the spacer and with the 5.5 Nm screw the clamp nut of the "2" stop screw. 
By using the "3" adjustment lever, start the vehicle's engine to 3,000    rpm. The pump will have to be replaced if the 
engine speed drops too slowly or lags below the engine stalls, or the idle speed or even both.
Inspect the adjustment of the cable throttle and adjust where need be.
Also inspect the adjustment on the potentiometer.
Turn the engine off but leave the ignition switched on.
Inspect the voltage supply of the potentiometer (see workshop manual).
Look at the diesel pump fault memory of the electronics with V.A.G 1551/1552 and if necessary take it away.
Then inspect the potentiometer voltage V.A.G 1551/1552 (see workshop manual). The voltage must be greater than 
0.2 V position and the voltage must be smaller than 4.8 V.
Remove the injection pump if this isn't so.

There is no response from the accelerator, vehicle is inoperative 
Lever broken on the shaft of the engine speed adjustment 
Cause: 
Loose injection pump bracket could be a possibility
Models affected: 
Golf, Passat Diesel
Any components, shaft of the engine speed adjustment lever or the injection pump are broken, investigate the joins 
of the injection pump bracket on the crankcase.
Three new bolts must always be fitted - Part No. N 102 260 02.

Engine doesn't start intermittently, frequently after a short drive, engine control unit is locked.
Cause: 
The electrical system breaks down when the starter motor engages. Consequently the engine control unit is locked. 
Vehicles with control unit Part No. 023 906 024 T and 44 Ah battery (model year 1996 only) are affected. 
Service: 
Look at the earth cable from battery to engine and especially the earth pin on the body below the battery and 
ensure it was installed properly.
Solution: 
The starting problem doesn't recur, if you wait two seconds
between turning on the ignition and starting the engine. 

Engine stalls sporadically when disengaging clutch after overrun/in warm weather 
Cause: 
Current engine adjustment.
After the overrun phase (overrun cut off), the fuel injection doesn't restart in time whilst in warm weather the air 
conditioning compressor is switched on.
Models affected: 
Optimised engine adjustment with engine control unit 
Part No. 4A0 907 473 K or 4A0 907 473 L. 
From Chassis No.: 
4A VN 063 250
8D VA 219 000
8G VN 006 500 
Service: 
1.	With optimised adjustment fit engine control unit.
2.	(Vehicles without traction slip control)  Part No. 4A0 907 473 K
3.	(Vehicles with traction slip control) Part No. 4A0 907 473 L
Only vehicles of MY 96: 
The relay for lambda sensor heating -J278 has been fitted should be investigated.    
Take away the relay for lambda sensor heating -J278 (if fitted) and bridge the contacts 30 and 87 to close the circuit. 
Position 1 on 3 connection carrier in the plenum chamber for installation location A4 (8D).
Position 1 on 6 connection carrier on the passenger side of the A pillar for installation location A6 (4A):.
Position 14 on 13 connection carrier under the passenger storage box for installation location Cabriolet:. 
Please Note: 
The control unit must be coded after the installation Workshop Manual MPFI Injection and Ignition System.