Inspection Procedure

HINT:

• Read freeze frame data using hand-held tester or OBD II scan tool. Because freeze frame records the engine conditions when a malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, etc. at the time of the malfunction.
• If the CAN communication malfunctions, there is no data output from the ECM. Some of the freeze frame data will not be correct and not identical with ECM data. In such a case, the ECM data are correct.

1. Check for open and short in harness and connector between transmission control ECU and ECM ( PROCEDURE  ). 
   1. NG: Repair or replace harness and connector. 
   2. OK: Go to next step 
2. Check resistance between terminals CAN+ and CAN- of transmission control ECU connector. 

   PREPARATION: 

   1. Connect the hand-held tester to the DLC3.
   2. Turn the ignition switch ON.

   CHECK: 

   Measure the resistance between terminals CAN+ and CAN- of transmission control ECU.

   OK: 

   1. The correct waveforms are as shown. 
   1. NG: Replace ECM. 
   2. OK: Go to next step 
   Fig 1: Normal Signal Waveform

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3. Replace transmission control ECU. 

   After replacing the transmission ECU, check that the problem disappears.

   1. NG: Replace ECM. 
   2. OK: END.