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INSPECTION PROCEDURE 13: Cannot communicate with the A/C compressor.
cautionIf there is any problem in the CAN bus lines, an incorrect diagnostic trouble code may be set. Prior to this diagnosis, always diagnose the CAN bus lines.
 
 
 
 
TECHNICAL DESCRIPTION (COMMENT)
The PHEV-ECU, the power supply or the ground connection to the A/C compressor or the A/C compressor itself may be defective when the PHEV-ECU cannot communicate with the A/C compressor inverter for at least eight seconds.
 
 
TROUBLESHOOTING HINTS
  • Malfunction of the A/C compressor assembly
  • The power supply or the ground connection to the A/C compressor fails
  • The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector
  • Malfunction of the PHEV-ECU
 
 
DIAGNOSIS
Required Special Tools:
  • MB991223: Harness Set
  • MB992006: Extra Fine Probe
STEP 1. Voltage measurement at A/C compressor assembly connector.
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Voltage between 12V terminal and body ground.
OK: The voltage should measure approximately 12 volts (battery positive voltage).
Is the check result normal?
Go to Step 3.
Go to Step 2.
 
STEP 2. Check of open circuit in 12V line between IGCT control relay and A/C compressor assembly connector.
Is the check result normal?
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).
Repair the connector(s) or wiring harness.
 
STEP 3. Resistance measurement at the A/C compressor assembly connector.
(1) Disconnect the connector, and measure at the wiring harness side.
(2) Continuity between A/C compressor ground terminal and body ground.
OK: The resistance should be 2 ohms or less
Is the check result normal?
Go to Step 4.
Go to Step 6.
 
STEP 4. Check of open circuit in COMH, COML line between PHEV-ECU connector and A/C compressor assembly connector.
Is the check result normal?
Go to Step 5.
Repair the connector(s) or wiring harness.
 
STEP 5. After replacing the PHEV-ECU (Refer to GROUP 54Da - PHEV-ECU ), using scan tool (M.U.T.-IIISE), read the A/C compressor assembly DTC is set.
(1)
cautionTo prevent damage to scan tool (M.U.T.-IIISE), always turn the electric motor switch to the OFF position 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) Turn the electric motor switch from OFF position to ON position.
(3) Check if DTC is set.
(4) Turn the electric motor switch to the OFF position.
Is the DTC set?
Replace the A/C compressor assembly (Refer to ).
Intermittent malfunction. Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points, - How to Cope with Intermittent Malfunctions ).
 
STEP 6. Check of open circuit in GND line between A/C compressor assembly connector and ground connector.
Is the check result normal?
The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ).
Repair the connector(s) or wiring harness.