Inspection Procedure

NOTE:

Before performing troubleshooting, inspect the connectors of related circuits.
Before replacing the suspension control ECU, perform all of the following again: 1) symptom simulation (see ELECTRONIC CIRCUIT INSPECTION PROCEDURE ); 2) DTC inspection; and 3) Intelligent tester or Techstream inspection (Data List or Active Test). If no malfunctions are found in other areas, replace the suspension control ECU.
If the suspension control ECU or height control sensor is replaced, the vehicle height offset calibration must be performed (see INITIALIZATION ).

CHECK DTC (AIR SUSPENSION SYSTEM)

Clear the DTC (see DTC CHECK / CLEAR ).
Perform a road test.

Check for DTC (see DTC CHECK / CLEAR ). Check if DTC C1783/ 83 and U0122/71 are output.

Result

DTC (AIR SUSPENSION SYSTEM)

Condition	Proceed to
Not output	A
Output	B

B: GO TO CAN COMMUNICATION SYSTEM (See CAN COMMUNICATION SYSTEM )

A: GO TO NEXT STEP

CHECK DTC (BRAKE CONTROL SYSTEM)

Check for DTC (see DTC CHECK/CLEAR ). Check if DTC C1783/ 83 and a brake control system speed sensor malfunction DTC (C0200/31, C0205/32, C0210/33, C0215/35, C1236/36, C1238/38 or C1239/39) are output.

Result

DTC (BRAKE CONTROL SYSTEM)

Condition	Proceed to
Not output	A
Output	B

B: GO TO BRAKE CONTROL SYSTEM (See DIAGNOSTIC TROUBLE CODE CHART )

A: GO TO NEXT STEP

CHECK VEHICLE SPEED SIGNAL (DATA LIST)

Turn the engine switch off.
Connect the Intelligent tester or Techstream to the DLC3.
Turn the engine switch on (IG) and turn the tester main switch on.
Enter the following menus:
1. Intelligent tester - Select: DIAGNOSIS / OBD/MOBD / CHASSIS / AIR SUSPENSION / DATA LIST /
2. Techstream - Select: Chassis / Air Suspension / Data List /

According to the display on the tester.

Intelligent tester

AIR SUSPENSION

INTELLIGENT TESTER - AIR SUSPENSION SPECIFICATION

Tester Display	Measurement Item/Range	Normal Condn	Diagnostic Note
FR WHEEL SPD	Front right wheel speed reading / min.: 0 km/h (0 mph) max.: 255 km/h (159 mph)	Actual vehicle speed	Speed indicated on speedometer
FL WHEEL SPD	Front left wheel speed reading/ min.: 0 km/h (0 mph) max.: 255 km/h (159 mph)	Actual vehicle speed	Speed indicated on speedometer
RR WHEEL SPD	Rear right wheel speed reading/ min.: 0 km/h (0 mph) max.: 255 km/h (159 mph)	Actual vehicle speed	Speed indicated on speedometer
RL WHEEL SPD	Rear left wheel speed reading/ min.: 0 km/h (0 mph) max.: 255 km/h (159 mph)	Actual vehicle speed	Speed indicated on speedometer

Techstream

Air suspension

TECHSTREAM - AIR SUSPENSION SPECIFICATION

Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
FR Wheel Speed	Front right wheel speed reading / min.: 0 km/h (0 mph) max.: 255 km/h (159 mph)	Actual vehicle speed	Speed indicated on speedometer
FL Wheel Speed	Front left wheel speed reading/ min.: 0 km/h (0 mph) max.:255 km/h (159 mph)	Actual vehicle speed	Speed indicated on speedometer
RR Wheel Speed	Rear right wheel speed reading/ min.: 0 km/h (0 mph) max.: 255 km/h (159 mph)	Actual vehicle speed	Speed indicated on speedometer
RL Wheel Speed	Rear left wheel speed reading/ min.: 0 km/h (0 mph) max.: 255 km/h (159 mph)	Actual vehicle speed	Speed indicated on speedometer

OK: Vehicle speed indicated on the tester indicates the actual speed.

NG: GO TO BRAKE CONTROL SYSTEM (See HOW TO PROCEED WITH TROUBLESHOOTING )

OK: REPLACE SUSPENSION CONTROL ECU (See REMOVAL )