Pinpoint Test E: DTCs C1790 (LR) and C1795 (RR)
Vehicle Dynamic Suspension
Pinpoint Tests
Pinpoint Test E: DTCs C1790 (LR) and C1795 (RR)
Refer to Wiring Diagram Set 41, Vehicle Dynamic Suspension for schematic and connector information. Diagrams By Number
Normal Operation
The Vehicle Dynamics Module (VDM) will command the air spring solenoid(s) ON or OFF when certain conditions are met. The left solenoid receives voltage from the VDM along circuit CCL05 (WH/BN), the right solenoid receives voltage from the VDM along circuit CCL07 (YE/GY). The 2 solenoids share a common ground along circuit GD120 (BK/GN).
- DTC C1790 (LR Air Suspension Air Spring Solenoid Output Circuit Failure) - With the ignition in the RUN position and during a deflate (vent) or inflate (pump) activity, if the VDM detects an open, a short to voltage or a short to ground on the LR air spring solenoid output circuit, DTC C1790 will be set.
- DTC C1795 (RR Air Suspension Air Spring Solenoid Output Circuit Failure) - With the ignition in the RUN position and during a deflate (vent) or inflate (pump) activity, if the VDM detects an open, a short to voltage or a short to ground on the RR air spring solenoid output circuit, DTC C1795 will be set.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Air spring solenoid(s)
- VDM
PINPOINT TEST E: DTCs C1790 (LR) AND C1795 (RR)
NOTICE: Use the Flex Probe Kit for all test connections to prevent damage to the wiring terminals. Do not use standard multi-meter probes.
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E1 CHECK THE AIR SPRING SOLENOID PID
- Connect the scan tool.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: DataLogger VDM.
- Monitor the following VDM PIDs:
- Left rear solenoid driver short to ground (LSOL_DR_STG)
- Right rear solenoid driver short to ground (RSOL_DR_STG)
- Do the PIDs indicate a short to ground?
Yes
GO to E3.
No
GO to E2.
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E2 CHECK THE AIR SPRING SOLENOID CONNECTOR(S)
- Disable the air suspension system. Refer to Air Suspension System Disable/Enable Air Suspension System Disable/Enable.
- Using the DTCs obtained after running the VDM self-test, determine which air spring solenoid is causing the concern.
- Ignition OFF.
- Disconnect: Suspect Air Spring Solenoid Connector.
- Inspect the pins and terminals of the air spring solenoid connector(s) for corrosion, damage, pushed-out pins, spread terminals, moisture or other damage.
- Is the air spring solenoid connector(s) OK?
Yes
GO to E3.
No
REPAIR the connector(s) as necessary. CLEAR the DTCs. REPEAT the self-test.
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E3 CHECK THE AIR SPRING SOLENOID CONTROL CIRCUIT(S) FOR A SHORT TO GROUND
- Disable the air suspension system. Refer to Air Suspension System Disable/Enable Air Suspension System Disable/Enable.
- Ignition OFF.
- Disconnect: VDM C2131b.
- Disconnect: Air Spring Solenoids C4044 LR and C4045 RR.
- Measure the resistance between C4044-1, circuit CCL05 (WH/BN), harness side and ground.
- Measure the resistance between C4045-1, circuit CCL07 (YE/GY), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
GO to E4.
No
REPAIR the affected circuit(s).
CLEAR the DTCs. REPEAT the self-test.
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E4 CHECK THE AIR SPRING SOLENOID CONTROL CIRCUIT FOR SHORT TO VOLTAGE
- Disable the air suspension system. Refer to Air Suspension System Disable/Enable Air Suspension System Disable/Enable.
- Ignition OFF.
- Disconnect: VDM C2131b.
- Disconnect: Air Spring Solenoids C4044 LR and C4045 RR.
- Ignition ON.
- For the LR air spring solenoid, measure the voltage between C4044-1, circuit CCL05 (WH/BN), harness side and ground.
- For the RR air spring solenoid, measure the voltage between C4045-1, circuit CCL07 (YE/GY), harness side and ground.
- Is any voltage present?
Yes
REPAIR the affected circuit(s). CLEAR the DTCs. REPEAT the self-test.
No
GO to E5.
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E5 CHECK CIRCUIT GD120 (BK/GN) FOR AN OPEN
- Ignition OFF.
- For the RR air spring solenoid, measure the resistance between C4045-2, circuit GD120 (BK/GN), harness side and ground.
- For the LR air spring solenoid, measure the resistance between C4044-2, circuit GD120 (BK/GN), harness side and ground.
- Is the resistance less than 5 ohms?
Yes
GO to E6.
No
REPAIR circuit GD120 (BK/GN). CLEAR the DTCs. REPEAT the self-test.
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E6 CHECK THE AIR SPRING SOLENOID COIL(S) FOR AN OPEN
- For the RR air spring solenoid, measure the resistance between air spring solenoid C4045 pin-1, component side and air spring solenoid C4045 pin-2, component side.
- For the LR air spring solenoid, measure the resistance between air spring solenoid C4044 pin-1, component side and air spring solenoid C4044 pin-2, component side.
- Is the resistance between 15 and 19 ohms (if the solenoid is very hot, the resistance may be as high as 22 ohms)?
Yes
GO to E7.
No
INSTALL a new air spring solenoid(s). REFER to Air Spring Solenoid Valve Service and Repair. CLEAR the DTCs. REPEAT the self-test.
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E7 CHECK THE VDM CONNECTOR
- Check the VDM connector for:
- corrosion.
- pushed-out pins.
- spread terminals.
- Connect: VDM C2131b.
- Make sure the connector is seated correctly then enable the air suspension system, operate the system and verify the concern is still present.
- Is the concern still present?
Yes
INSTALL a new VDM. REFER to Vehicle Dynamics Module (VDM) Service and Repair. CLEAR the DTCs. REPEAT the self-test.
No
The system is operating correctly at this time. Concern may have been caused by a loose or corroded connector.
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