DTC Advanced Diagnostics: U1608 (1073) (Generator Motor Control Module)
DTC U1608 (1073): EP-CAN Malfunction (Generator Motor Control Module - Battery Charge Control Module)
General Description
The controller area network (CAN) transmits/receives pulsing signals to/from the control modules simultaneously by using two signal lines (EPP-CAN A_H and EPP-CAN A_L). When the motor control module does not receive the signals from the battery charge control module via the EPP-CAN lines or the received data is abnormal for a specified time, a malfunction is detected and a DTC is stored.
Monitor Execution, Sequence, Duration, DTC Type
| Execution | Continuous |
| Sequence | None |
| Duration | 2.0 seconds or more |
| DTC Type | Two drive cycles, MIL off, POWER SYSTEM indicator on, 12 volt battery charging system indicator off |
Enable Conditions
| Condition | Minimum | Maximum |
|---|---|---|
| Elapsed time since the 12 volt battery voltage reaches to a specified value after the vehicle condition is turned to the ON mode | 5 seconds | - |
| 12 volt battery voltage | 10.2 V | - |
Malfunction Threshold
One of these conditions is met for at least 2.0 seconds:
- The motor control module does not receive any signals via the EPP-CAN lines.
- The information sent from the battery charge control module is abnormal.
Possible Cause
NOTE: The causes shown may not be a complete list of all potential problems, and it is possible that there may be other causes.
- EPP-CAN circuit EPP-CAN A_H line open
- EPP-CAN circuit EPP-CAN A_L line open
- EPP-CAN circuit EPP-CAN A_H line short to ground
- EPP-CAN circuit EPP-CAN A_L line short to ground
- IGA relay circuit IGHLDA/IG HOLD1 RLY CL- line short
- IGA relay circuit stuck on
- Unit communicating on EPP-CAN internal circuit failure
Diagnosis Details
Conditions for setting the DTC
When a malfunction is detected during the first drive cycle, a Pending DTC is stored in the motor control module memory. If the malfunction returns in the next (second) drive cycle, the POWER SYSTEM indicator comes on and a Confirmed DTC and the freeze data are stored in the motor control module memory.
Conditions for clearing the DTC
The POWER SYSTEM indicator is cleared if the malfunction does not return in three consecutive trips in which the diagnostic runs. The POWER SYSTEM indicator, the Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool Clear command or by disconnecting the 12 volt battery.