C1751

SUSPENSION CONTROL: AIR SUSPENSION SYSTEM: C1751/51: Continuous Electric Current to Height Control Compressor

DTC C1751/51 - Continuous Electric Current to Height Control Compressor

DESCRIPTION





*1: The relief pressure of the compressed air is 980 kPa (10 kgf/cm2, 142 psi).
If the vehicle height control is attempted on a steeply sloping road, when the vehicle is overloaded, or when the vehicle is jacked up with the engine running, the compressor motor operates continuously to raise vehicle height, and causes electric current to flow to the AIR SUS relay for 100 seconds or longer.
Thus DTC C1751/51 may be output and vehicle height control may be suspended. (This is not electrically abnormal.) In this case, however, the vehicle height operation is resumed approx. 10 min. after the ignition switch is turned ON after the ECU detects the first error. If ECU detects another error, it takes 70 minutes until control is resumed.

INSPECTION PROCEDURE

PROCEDURE

1. INSPECT HEIGHT CONTROL COMPRESSOR CIRCUIT
(a) Inspect the height control compressor circuit C1742.
NEXT -- Continue to next step.
2. INSPECT AIR LEAKAGE
(a) Check tube connections for air leakage Adjustments.
OK:
No leaks
NG -- REPAIR OR REPLACE AIR TUBE
OK -- Continue to next step.
3. INSPECT HEIGHT CONTROL VALVE (GATE SOLENOID, LEVELING SOLENOID, EXHAUST SOLENOID VALVE)
(a) When using the Techstream:
(1) Connect the Techstream to the DLC3.
(2) Turn the ignition switch ON and the Techstream on.
(3) Select the item "Rear Leveling Solenoid", "Rear Gate Solenoid", "Low Pressure Tank Solenoid", "Exhaust Solenoid" in the Active Test, and operate it with the Techstream.
(4) Check whether the solenoid makes a sound.
(5) Check whether the height control solenoid valve has continuity (will vibrate).
OK:
The solenoid makes a sound, and the height control solenoid valve has continuity. (It will vibrate.)




(b) When not using the Techstream:
(1) Disconnect the valve connectors.
(2) Check the operating sound of the valves when battery positive voltage is applied to the terminals as shown below.






OK:
It makes an operating sound (click).
- When a malfunction is found in the gate solenoid valve, the leveling valve or the tank solenoid valve, replace the height control reservoir assembly.
- When a malfunction is found in the exhaust solenoid valve, replace the height control compressor assembly.

C -- REPLACE HEIGHT CONTROL COMPRESSOR ASSEMBLY
B -- REPLACE HEIGHT CONTROL RESERVOIR ASSEMBLY
A -- Continue to next step.
4. INSPECT HEIGHT CONTROL SENSOR LINK SUB-ASSEMBLY
(a) Inspect and adjust the height control sensor link sub-assembly.
NEXT -- Continue to next step.
5. CONFIRM DTC
(a) Clear the DTC and repeat the procedure to re-check it Air Suspension System.
HINT: If the DTC C1751/51 is still output, proceed to the next step.

NEXT -- REPAIR OR REPLACE PARTS AND COMPONENTS INDICATED BY OUTPUT DTCS