VW Golf

Would a faulty ecu cause a gti golf not to run on all four cylinders?

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Wiki User
2008-12-16 20:16:36

It is very unlikely that an ECU issue would cause the above

problem, and would certainly not affect mk2 and mk3 GTIs due to

their distributor-based ignition system.

Not running on all cylinders is primarily due to a lack of spark

on the affected cylinder.

On earlier vehicles (including GTIs with mechanical injection

and no ECU) the spark may not form at the spark plug due to * a

broken spark plug * a broken spark plug lead (commonly referred to

as a high tension/HT lead) * damaged insulation on an HT lead

(allowing the high voltage to find a path to the vehicle's

electrical ground) * a damaged/worn distributor cap Later

(distributorless) vehicles can have problems with coil-packs (as

seen on the VR6 engines) or coil units (as seen on the 1.8T


Any vehicle with a faulty ECU is most likely to either not start

at all or run in LOS mode. LOS stands for Limited Operation

Strategy and is comparable to 'Safe Mode' on a home computer. In

this mode the car should still run, albeit with reduced power

output. LOS mode is usually triggered by the ECU detecting a fault

condition, faulty sensor or faulty actuator. LOS mode would not

cause the vehicle to run on fewer cylinders.

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