Diagnostic Overview
Each time the ECH is powered on, a pre-drive check of the throttle valve system is performed.
Positioning of the throttle valve:
The first test is a rationality check of the control loop: A target position is set and the reaction of the position sensor is checked.
If the position is not within the target position tolerance, a fault code "Gest ngetest" (P1628, P161F) is generated.
Adaptation:
The next step is the adaptation of the Zero-Position. After the adaptation is done, the value is checked by the following tests:
- Actuator detected an error: generate false code P0123, P0223
- Signal range is too high: generate false code P0121, P0221
- Value out of range, if not false code P0122, P0222
Safety Switch Off:
The third test is a verification of the safety switch of by the supervisor processor: Before activation of the main processor, the supervisor processor switches off the actuator. If the throttle valve is opening, the error code "Enable-Leitung fehlerhaft" (P1628, P161F) is generated.
Additional the Safety Switch Off is electrically checked all the time. The following errors could detected by the hardware: "Short to GND" (P156D, P157D), "Short to UB" (P156E, P157E) and "Openload" (P156F, P157F).