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Removing and installing engine control unit J623 with protective housing (Touran) — VW

Removing and installing engine control unit J623 with protective housing (Touran) on VW: factory workshop procedure for engines CDGA.

Workshop procedure for VW — the factory write-up, straight from real workshop data.

factory workshop text 1 engine code

🔧 Engine codes this applies to

📋 Procedure

ℹ️ Torque figures below come verbatim from workshop data — always cross-check against your vehicle's factory manual before final tightening.

Removing and installing engine control unit
J623 with protective housing (Touran)
Special tools and workshop equipment required
Hot air blower from wiring harness repair set
VAS 1978
Nozzle attachment from wiring harness repair set
VAS 1978
If you wish to renew the engine control unit, connect the
Vehicle diagnostic tester and carry out the guided function
“Renew control unit”.
Removing
Switch off ignition.
Remove wiper arms and plenum chamber cover (repair group 92: Windscreen wiper system; Removing and installing windscreen wiper system).
Remove plenum chamber bulkhead (repair group 50: Body - front; Plenum chamber bulkhead).
Note
The shear-head bolt threads are coated with locking compound. Heating the shear-head bolt with a hot air blower releases the locking effect of the locking compound.
Caution
Cover lines, connections and control units in the vicinity of the engine control unit to prevent damage through heat.
Perform settings on hot air blower (4) as shown:
Turn temperature setting potentiometer (2) to maximum heat output (600°C).
Set two-stage switch for volume of air (3) to position 3.
WARNING
When shear-head bolts are heated up, parts of the protective housing will be subjected to a large amount of heat. Wear protective gloves to avoid possible injury.
Place nozzle of hot air blower close to shear-head bolt.
Switch on hot air blower and heat bolt for about 20 to 25 seconds.
Unscrew shear-head bolt using mole grips on bolt head.
The procedure for the second shear-head bolt is identical.
Then remove securing nuts for control unit bracket (arrows).
Release connectors on engine control unit and pull off connector.
Press catches (1) and (2) outwards. Then pull engine control unit off control unit bracket in direction of arrow.
Installing
Push engine control unit onto control unit bracket until it engages in catches.
Fit connectors to engine control unit and lock in position.
Tighten securing bolts (arrows) to 10 Nm.
Install cover of protective housing.
Tighten new shear-head bolts (arrows) evenly until heads shear off.
Install plenum chamber bulkhead (repair group 50: Body - front; Plenum chamber bulkhead).
Install wiper arms and plenum chamber cover (repair group 92: Windscreen wiper system; Removing and installing windscreen wiper system).

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TorqFix was built by a mechanic — after a 2,700 km drive with five roadside repairs that no diagnostic tool could explain.

The figures on this page come from manufacturer workshop documentation and are shown as they are. The page is assembled automatically from that data — it is not written by an AI. The AI works in the chat, where it answers for your specific car. It writes nothing here.

Variants of the same model differ. Cross-check torque against the factory manual for your engine before final tightening.

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Workshop data on this page last updated 20 Sep 2026.