C1790

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Circuit Description
The ESC module supplies 5 volts and a ground to the ride control switch's voltage divider circuit. The ride control switch changes the resistance value of the switch circuit which alters the voltage level at the ESC module terminal A7. There are three possible voltage levels, and each voltage level corresponds to a switch selection position (TOUR, SPORT, PERF). The ESC module monitors the voltage level received from the ride control switch, and will set a DTC if the detected voltage level is not within the calibrated amount.

Conditions for Setting the DTC
- The ESC module detects that the ride control switch voltage level is under 0.5 volts or over 4.5 volts.
- The condition must be detected for 5 seconds.

Action Taken When the DTC Sets
- Stores a DTC C1790 in the ESC memory.
- Provides shock absorber solenoid control based on the SPORT setting.
- Sends a message to the IPC to display the SERVICE RIDE CONTROL message.

Conditions for Clearing the DTC
- A history DTC will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present.
- The ESC module detects that the ride control switch voltage level is 0.5-4.5 volts.
- The On-Board Diagnostic (Clearing DTCs) feature.
- Using a scan tool.

Diagnostic Aids
The following conditions may cause an intermittent malfunction to occur:
- An intermittent open or short in the ride control switch circuit.
- An internal open or short in the ride control switch.
- If the DTC is a history DTC, the problem may be intermittent. Using a scan tool, monitor the ride control switch voltage while moving the wiring and the connectors. This can often cause the malfunction to appear.


Test Description
The numbers below refer to the step numbers on the diagnostic table:
2. This step checks if the ESC module is able to receive the ride control switch and respond to the change in resistance values.
3. This step measures the internal resistance or the ride control switch.
4. This step checks if the ESC module is able to send a correct reference signal to the ride control switch.
5. This step checks if the ESC module can respond to a change in resistance values.
6. This step checks for an intermittent malfunction and requests a thorough inspection of the related ride control switch circuit wiring and connectors.