Circuit Description
The suspension control module provides a common regulated voltage of approximately 5 volts to all four of the (body-to-wheel) position sensors, RTD air pressure sensor and the steering handwheel position/speed sensor. The suspension control module monitors this reference voltage for any malfunctions that could prevent it from outputting a regulated 5 volts.
Conditions for Running the DTC
Continuously with the ignition on.
Conditions for Setting the DTC
The suspension control module senses a sensor reference voltage of less than 4.0 volts or greater than 6.0 volts.
Action Taken When the DTC Sets
| • | Disable all EVO outputs. |
| • | Disable all compressor leveling functions, and assume default pressure. |
| • | Disable all shock solenoid valve outputs. |
| • | The SERVICE RIDE CONTROL message will be displayed. |
| • | Stores a DTC C0870 in the suspension control module memory. |
Conditions for Clearing the DTC
| • | The suspension control module senses the correct voltage output to the position sensors upon the next ignition cycle. |
| • | Using a scan tool. |
| • | A history DTC will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present. |
Diagnostic Aids
| • | The following conditions may cause a malfunction to occur: |
| - | A short to voltage in any one of the (body-to-wheel) position sensor reference voltage circuit. |
| - | A short to ground in any one of the (body-to-wheel) position sensor reference voltage circuit. |
| • | If the circuit is shorted to ground the scan tool will display all position sensor voltage as zero. |
| • | If the circuit is shorted to a unwanted voltage source, the scan tool may display all position sensor voltage as that voltage. |
| • | A short to voltage in the 5 volt reference of the RTD air pressure sensor. |
| • | A short to ground in the 5 volt reference of the RTD air pressure sensor. |
| • | A short to voltage in the 5 volt reference of the steering handwheel position/speed sensor. |
| • | A short to ground in the 5 volt reference of the steering handwheel position/speed sensor. |
| • | A intermittent malfunction or DTC may cause a random firm/soft ride condition. |
Test Description
The number(s) below refer to the step number(s) on the diagnostic table.
-
Tests whether the condition is module, system, or condition related.
-
Tests whether the condition has been corrected or identified as specified in the supporting text.
-
Tests all position sensors reference voltage circuits.
-
Tests the 5 volt reference circuit of the steering handwheel position/speed sensor for a short to ground and a short to voltage.
-
Tests the 5 volt reference circuit of the RTD air pressure sensor for a short to ground and a short to voltage.
-
Clear DTCs and checks to see if DTC will reset.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Suspension Controls Schematics | |||
1 | Did you perform the RTD Diagnostic System Check? | Go to Step 2 | |
2 |
Does the scan tool indicate that DTC C0870 is current? | Go to Step 4 | Go to Step 3 |
Since most occurrences of this DTC are caused by a short to ground or short to voltage in a sensor reference voltage circuit, review the RTD System or, with the customer to verify the conditions under which the DTC set. Did vehicle operation cause this DTC to set? | Go to Diagnostic Aids | Go to Step 4 | |
Does the DTC reset? | Go to Step 5 | System OK | |
Test all 4 (body-to-wheel) position sensor 5 volt reference circuits for a short to ground and a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? |
Go to Step 9 | Go to Step 6 | |
Test the steering handwheel position/speed sensor 5 volt reference circuit for a short to ground and a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 9 | Go to Step 7 | |
Test the RTD air pressure sensor 5 volt reference circuit for a short to ground and a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 9 | Go to Step 8 | |
8 |
Important: After replacement, use the scan tool to perform the set up procedure (re-calibrate) located under Special Functions (F8: Recalibration) for the suspension control module. Replace the suspension control module. Refer to Electronic Suspension Control Module Replacement . Did you complete the replacement? | Go to Step 9 | -- |
Does the DTC reset? | Go to Step 2 | System OK | |
