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Inspection Procedure 2: The OSS-ECU (IG1) signal is not received.
 
 
cautionBefore replacing the ECU, ensure that the power supply circuit, the ground circuit and the communication circuit are normal.
 
 
TECHNICAL DESCRIPTION (COMMENT)
If there is an error to the input signal (IG1) from the OSS-ECU, or if the IG relay in ETACS-ECU does not function normally, the ignition switch (IG1) signal is no longer output to the communication line.
 
 
TROUBLESHOOTING HINTS
  • The ETACS-ECU may be defective
  • The OSS-ECU may be defective
  • The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector
 
 
DIAGNOSIS
Required Special Tools:
  • MB991223: Harness Set
  • MB992006: Extra Fine Probe
STEP 1. Voltage measurement at ETACS-ECU connector (IG1 terminal).
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Press the electric motor switch to turn on the power supply mode.
(3) Check the voltage between the ETACS-ECU connector (IG1 terminal) and ground.
OK: The voltage should measure approximately 12 volts (battery positive voltage).
Is the check result normal?
Go to Step 4.
Go to Step 2.
 
STEP 2. Using scan tool (M.U.T.-IIISE), read the OSS DTC.
(1)
cautionTo prevent damage to scan tool (M.U.T.-IIISE), always turn off the power supply mode of the electric motor switch before connecting or disconnecting scan tool (M.U.T.-IIISE).
Connect scan tool (M.U.T.-IIISE). Refer to "How to connect the Scan Tool (M.U.T.-IIISE) ."
(2) Press the electric motor switch to turn on the power supply mode.
(3) Check whether the OSS-ECU sets a DTC.
Is the DTC set?
Diagnose the OSS-ECU. Refer to GROUP 42B, Troubleshooting .
Go to Step 3.
 
STEP 3. Check of short to power supply, short to ground, and open circuit in IG1 line between OSS-ECU (IG1) and ETACS-ECU connector.
Is the check result normal?
Go to Step 4.
Repair the connector(s) or wiring harness.
 
STEP 4. Using scan tool (M.U.T.-IIISE), check data list.
Check the input signal from the ignition switch (IG1).
  • Turn the ignition switch to the "ON" position.
 
Item No.Item nameNormal condition
254IG voltageBattery positive voltage
OK: Normal condition is displayed.
Is the check result normal?
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ).
Replace the ETACS-ECU.