ECU Power Source Circuit

SUSPENSION CONTROL: AIR SUSPENSION SYSTEM: ECU Power Source Circuit

ECU Power Source Circuit

DESCRIPTION

When the power switch is ON (IG), the passenger side junction block AIRSUS relay turns ON, and power is supplied to the suspension control ECU.

WIRING DIAGRAM





INSPECTION PROCEDURE
NOTICE:
- Before performing troubleshooting, inspect the connectors of related circuits.
- Before replacing the suspension control ECU, perform all of the following again: 1) symptom simulation 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 Testing and Inspection.

PROCEDURE

1. CHECK IG VOLTAGE (DATA LIST)
(a) Turn the power switch OFF.
(b) Connect the intelligent tester or Techstream to the DLC3.
(c) Turn the power switch ON (IG) and the tester ON.
(d) Enter the following menus:
(1) Intelligent tester - Select: DIAGNOSIS / OBD/MOBD / CHASSIS / AIR SUSPENSION / DATA LIST.
(2) Techstream - Select: Chassis / Air suspension / Data List.
(e) Check the values by referring to the table below.
(1) Intelligent tester

AIR SUSPENSION





(2) Techstream

Air suspension





OK:
11 to 14 V
NG -- INSPECT FUSE (AIRSUS)
OK -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
2. INSPECT FUSE (AIRSUS)
(a) Remove the AIRSUS fuse from the passenger side junction block.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- CHECK HARNESS AND CONNECTOR (PASSENGER SIDE JUNCTION BLOCK - ECU)
OK -- Continue to next step.
3. INSPECT PASSENGER SIDE JUNCTION BLOCK (AIRSUS RELAY)
(a) Disconnect the L88 ECU connector.





(b) Measure the voltage according to the value(s) in the table below.
Standard voltage:






NG -- CHECK HARNESS AND CONNECTOR (PASSENGER SIDE JUNCTION BLOCK - ECU AND BODY GROUND)
OK -- REPLACE SUSPENSION CONTROL ECU
4. CHECK HARNESS AND CONNECTOR (PASSENGER SIDE JUNCTION BLOCK - ECU AND BODY GROUND)
(a) Disconnect the L88 ECU connector.
(b) Disconnect the PA passenger side junction block connector.
(c) Measure the resistance according to the value(s) in the table below.





Standard resistance:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
5. CHECK HARNESS AND CONNECTOR (AUXILIARY BATTERY - PASSENGER SIDE JUNCTION BLOCK)
(a) Disconnect the PL passenger side junction block connector.





(b) Measure the voltage according to the value(s) in the table below.
Standard voltage:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
6. CHECK HARNESS AND CONNECTOR (MAIN BODY ECU - PASSENGER SIDE JUNCTION BLOCK AND BODY GROUND)
(a) Disconnect the PA passenger side junction block connector.





(b) Measure the voltage and resistance according to the value(s) in the table below.
Standard voltage:






Standard resistance:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
7. CHECK HARNESS AND CONNECTOR (PASSENGER SIDE JUNCTION BLOCK - ECU)
(a) Disconnect the L88 ECU connector.
(b) Connect the PA passenger side junction block connector.





(c) Measure the resistance according to the value(s) in the table below.
Standard resistance:





HINT: If the fuse is blown, replace the fuse.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE PASSENGER SIDE JUNCTION BLOCK