DTC Advanced Diagnostics: P06E4: General Description

Courtesy of HONDA, U.S.A., INC.

To supply power (FI_MAIN_RLY_OUT) for the powertrain control module (PCM), the PGM-FI main relay 1 drive request that is generated from the logical sum of the external signal (IG1_FUEL_PUMP) and the internal signal (PGM-FI main relay 1 drive request and soak timer) drives the FI_MAIN_RLY_CL- terminal, and turns the PGM-FI main relay 1 on. The soak timer continues to measure the time during off of the microcomputer (MCU) by supplying power from the +B_VBU line. The soak timer line drives to turn the PGM-FI main relay 1 on by the activation timer that is set at the time of MCU off and activates the MCU. The PCM performs the diagnosis of the soak timer with the following methods.

• Timer check

  The soak timer is activated in normal driving condition to measure the time that is used for comparing with the time measured in the MCU after the vehicle is turned to the OFF (LOCK) to detect the lowering of accuracy and counting stop of the counter in the soak timer. If there is a time difference between them, the PCM detects a malfunction and stores a DTC.

• Full count check

  The counter in the soak timer is counted to a maximum value after the vehicle is turned to the OFF (LOCK) mode to detect failure of the counter. If the counter cannot count to a maximum value, the PCM detects a malfunction and stores a DTC.

• Driver IC settings check

  The MCU reads out a value from the driver IC via serial communication if the settings for waking up the system is appropriately set. If the two values read out from the driver IC are different, the PCM detects a malfunction and stores a DTC.

• Wake up check

  The PCM confirms if the system woke up at the set timing at the time of the system wake up. If the system does not wake up at the expected timing or after the vehicle is turned to the ON mode, the PCM detects a malfunction and stores a DTC.

Monitor Execution, Sequence, Duration, DTC Type