Advanced Diagnostics

Advanced Diagnostics - DTC P1658: Electronic Throttle Control System (ETCS) Control Relay ON Malfunction (Engine Type: K24Z7)

General Description






The electronic throttle control system controls the throttle valve opening. The system includes the throttle actuator, the throttle valve, throttle position (TP) sensors A and B, the electronic throttle control system (ETCS) control relay, the accelerator pedal position (APP) sensor, and the engine control module (ECM). When the accelerator pedal is pressed, the APP sensor detects the accelerator pedal opening value. The accelerator pedal opening value is converted to a signal in the APP sensor and transmitted to the ECM to compute the target position. The ECM determines the throttle valve target position according to the signal received and operates the throttle actuator to move the throttle valve to the target position. The actual throttle valve position is determined by TP sensors A and B (installed in the throttle body). When the voltage is applied from the ETCS control relay to the VB ETCS terminal for a set time after the ETCS control relay is turned off, the ECM detects a malfunction in the ETCS control relay power switch and stores a DTC.

Monitor Execution, Sequence, Duration, DTC Type, OBD Status






Enable Conditions






Malfunction Threshold
The communication signal is input from the ECM for at least 2.0 seconds after the ETCS control relay is turned off.

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.

- ETCS control relay failure
- ETCS control relay DBW_RLY_CL- line short to ground
- ECM failure

Diagnosis Details

Conditions for setting the DTC
When a malfunction is detected, the MIL comes on and a Pending DTC, a Confirmed DTC, and the freeze data are stored in the ECM memory.

Conditions for clearing the DTC
The MIL is cleared if the malfunction does not return in three consecutive trips in which the diagnostic runs. The MIL, the Pending DTC, the Confirmed DTC, and the freeze data can be cleared with the scan tool Clear command or by disconnecting the battery.