Checking electronically regulated cooling system: VW Golf IV / Bora 1.6 (AEH, AKL, APF)

🧭 Before you start

Fits: VW Golf IV / Bora (1J)

Don't miss

• The plausibility of the system is checked. "“Syst. OK”" can be displayed even though an electrical fault has been detected.
• Read coolant temperature figures in display zones 1 and 2. Specification: The temperature at the engine outlet (display zone 1) must always be higher than the temperature at the radiator outlet (display zone 2).
• If the coolant temperature sender G62 or the coolant temperature sender at radiator outlet G83 or the wiring/connections or the radiator output stages are faulty, the radiator fan speed(s) will be activated.

🔧 Engine codes this applies to

📐 10 workshop diagrams for AEH

Real factory drawings for this job — timing marks, bolt locations and routing. Locked in the free view.

📋 Procedure

1. Connect fault readerV.A.G 1551 (vehicle system testerV.A.G 1552). Start engine and select "“Address word”" 01 of engine control unit.
2. Press keys 0 and 8 for function "“Read measured value block”" and confirm entry with Q key.
3. Press keys 1, 3 and 0 for "“Display group number 130”" and confirm entry with Q key.
4. Read result of system test in display zone 4. Specification: "“Syst. OK.”" [Note: The plausibility of the system is checked. "“Syst. OK”" can be displayed even though an electrical fault has been detected.]
5. Read coolant temperature figures in display zones 1 and 2. Specification: The temperature at the engine outlet (display zone 1) must always be higher than the temperature at the radiator outlet (display zone 2).

6. Change to display group 131 as follows: fault readerV.A.G 1551: press key 3 vehicle system testerV.A.G 1552: press key ↑.
7. Allow engine to continue to run at idling speed and observe the left "bit" in display zone 4: Specification "“0”".
8. Read fault memory: 01 [Note: If the coolant temperature sender G62 or the coolant temperature sender at radiator outlet G83 or the wiring/connections or the radiator output stages are faulty, the radiator fan speed(s) will be activated.]
9. Evaluate the remaining "bits" in display zone 4 of display group 131: 01.
10. Press the → key.
11. Press keys 0 and 6 for function "“End output”" and confirm entry with Q key.

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