Tachograph power supply interruption
* Check the wiring and the A connector at the back of the tachograph: - Damaged wiring or connector? - Loose connector? - Poor connection? * Check the power supply levels of the tachograph also during start: - Read terminal 30 voltage level: RDI 0xFD01 byte 1. Gain: 0,1 V/bit, Offset: 0 V, Range: 0V ... 6425,5V (0...64255 / 0x0000...0xFAFF). Shall be within: 9…33 V (0x005A … 0x014A). - Measure terminal 15 voltage level on pin A3. Shall be within 9…33 V. * Check the tachograph A connector pin assignment: - Pin A1: terminal 30 (Permanent voltage). - Pin A3: terminal 15 (Ignition). - Pin A5: minus (-). - Pin A6: ground. * Replace defective components. * Replace the tachograph.
What you'll see
No driver-visible symptom recorded.
System reaction
MC31/EV406: * Event warning message with error text "power interruption" together with Memory Code 31 is shown in the tachograph display. * The warning message will be displayed repetitively every hour until the cause is withdrawn. * Event stored in the tachograph memory * Event stored and in the inserted tachograph card. * System event in TCO1 CAN message is set to active. * Tachograph warning (amber T) is displayed in the instrument cluster.
Diagnostic depth
The tachograph has detected a power interruption: * Over voltage (power supply > ~33 V). The DTC is set once the power supply drops below 32,1 V. * Under voltage (power supply < ~8,6 V). The DTC is set once the power supply is above ~9,2 V. Power interruption (Over voltage): If the voltage supply of the tachograph rises above 33,0 V the tachograph switches to an “over-voltage” mode. Following functions are disabled in an “over-voltage” mode: * Printing or displaying data * Insertion or removal of the tachograph card. As soon as the voltage supply of the tachograph drops below 32,1 V, into the specified range, the tachograph returns to normal operating mode and indicates a “power interruption”. Power interruption (Under voltage): If the voltage supply of the tachograph drops below the following critical value of the specified range, the tachograph detects a “power interruption”: Typ. 8,6 V (min. 8,2 V; max 9,0 V) If the supply voltage of the tachograph rises again above the following critical value, the tachograph signals “power interruption”: Typ. 9,2 V (min. 8,7 V; max 9,7 V)
* Power interruption. * Over voltage. * Under voltage. * Fault in the cable harness.