Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
64 99... Reading out flashcode
Test precondition:
Check function of independent park heater,
refer to 64 12 005 CHECKING FUNCTION OF INDEPENDENT HEATING (THERMO TOP S)
Instruction:
Connect inspection lamp to glow plug above peripherals box. See appropriate SYSTEM WIRING DIAGRAM. Switch on independent heating via MID or on-board monitor, switch off after 3 minutes running time and, once after-running time has elapsed, count the number of flash pulses.
Flashcode evaluation
| Flash pulses | Fault cause and corrective measures |
|---|---|
| 1 | Flame detector has short or break, refer to FAULT 02 FLAME DETECTOR |
| 2 | Overvoltage or undervoltage at heater, charge battery. |
| 3 | Temperature sensor has short-circuit, refer to FAULT 05 TEMPERATURE SENSOR |
| 4 | Flame detector defective (does not detect flame), refer to FAULT 02 FLAME DETECTOR |
| 5 | Flame detector defective (always detects flame), refer to FAULT 02 FLAME DETECTOR |
| none | Combustion air blower or, refer to FAULT 01 COMBUSTION AIR BLOWER glow plug or, refer to FAULT 03 GLOW PLUG metering pump defective. refer to FAULT 06 PARK HEATING METERING PUMP |
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.