AD83.70-W-6000-49A | AHE test of electrical system heater unit flame cuts out at full load |
| Scope of test | Measuring instrument/ Test connection | Operation/Requirement | Specified value | Possible cause/Remedy | ||
1.0 | Flame cuts out at full load Heater unit function | | Ignition: ON Allow heater unit to cool down. Switch off engine preheating switch on center waist rail and vehicle blower if necessary. Switch heater unit on again. | If a different fault code appears: Carry out appropriate test steps. If no fault code appears: 1.1 | |||
1.1 | Flame cuts out at full load Temperature switch threshold | | Ignition: ON Heater unit: ON Engine preheating: OFF Check HHT actual values 01 and 02 Check temperature switch thresholds: Full load up to approx. | Temperature increases rapidly, above 90 °C: Check circulation pump (actuation). Coolant circulation disrupted , possible air in system. If no faults can be determined and fault code re-appears: - Check plug connections in circuit for temperature sensor and flame monitor for contact resistance. - Replace temperature sensor and flame sensor on trial. Temperature switch thresholds correspond and fault code re-appears: Replace control unit (Z14) on trial. | |||