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Diagnostic Item 16: Diagnose when the scan tool (M.U.T.-III) cannot receive the data sent by engine control module (ECM).
 
 
cautionWhen servicing a CAN bus line, ground yourself by touching a metal object such as an unpainted water pipe. If you fail to do, a component connected to the CAN bus line may be broken.
 
 
FUNCTION
The diagnostic result demonstrates that "the scan tool (M.U.T.-III) cannot receive the sent data from the engine control module (ECM)" when the scan tool (M.U.T.-III) checks the periodically sent data from each ECU and cannot receive the engine control module (ECM) data only.
 
 
TROUBLE JUDGMENT CONDITIONS
scan tool (M.U.T.-III) judges the trouble when the periodically sent data from engine control module (ECM) cannot be received.
 
 
PROBABLE CAUSES
  • Damaged harness wires and connectors
  • Power supply circuit malfunction of the engine control module (ECM)
  • Malfunction of the engine control module (ECM)
 
 
DIAGNOSIS
STEP 1. Connector check: joint connector (CAN2) and engine control module (ECM) connector
cautionThe strand end of the twist wire should be within 10 cm (4 inches) from the connector. For details refer to .
When checking the joint connector, ensure that its wiring harness side and its short pins are not damaged.
Is the check result normal?
Go to Step 2.
Repair the defective connector. Replace the joint connector as necessary.
 
STEP 2. Resistance measurement at joint connector (CAN2) and engine control module (ECM) connector.
cautionA digital multimeter should be used. For details refer to .
cautionThe test wiring harness should be used. For details refer to .
(1) Disconnect the joint connector (CAN2) and the engine control module (ECM) connector, and measure at the wiring harness side.
(2) Turn the ignition switch to the "LOCK" (OFF) position.
(3)
cautionWhen measuring the resistance, disconnect the negative battery terminal. For details refer to .
Ensure that the negative battery terminal is disconnected.
(4) Continuity between joint connector (CAN2) terminal No.11 and engine control module (ECM) connector terminal No.101
OK: Continuity (2 Ω or less)
(5) Continuity between joint connector (CAN2) terminal No.22 and engine control module (ECM) connector terminal No.102
OK: Continuity (2 Ω or less)
cautionStrictly observe the specified wiring harness repair procedure. For details refer to .
Is the check result normal?
<All the resistances measure 2 Ω or less> Go to Step 3.
<Either or all of the resistances measure more than 2 Ω> Repair the wiring harness between joint connector (CAN2) and the engine control module (ECM).
 
STEP 3. Resistance measurement at engine control module (ECM) connector.
cautionA digital multimeter should be used. For details refer to .
(1) Remove the engine control module (ECM), and measure at the equipment side.
(2) Resistance between engine control module (ECM) connector terminal No.101 and 102
OK: 120 ± 20 Ω
cautionStrictly observe the specified wiring harness repair procedure. For details refer to .
Is the check result normal?
<Within 120 ± 20 Ω> Power supply to the engine control module (ECM) may be suspected. Diagnose the fuel system. Refer to GROUP 13A - Troubleshooting .
<Not within 120 ± 20 Ω> Replace the engine control module (ECM).