5A
DTC P1777 (No.76): TCM Lost Communication with ECM (Reception Error) (M13A Model with VVT)
Wiring Diagram
1. ECM [A]: Terminal arrangement of TCM connector (M13 engine model with VVT) (viewed from harness side)
2. TCM [B]: Terminal arrangement of ECM connector (M13 engine model without VVT) (viewed from harness side)
DTC Detecting Condition and Trouble Area
DTC detecting condition Trouble area
Reception error of communication data for ECM is detected more than specified time continuously.
• ECM
• TCM
• CAN circuit
DTC Confirmation Procedure
1) Connect scan tool to DLC with ignition switch OFF.
2) Clear DTCs in TCM and ECM memories.
3) Start engine and run it for 1 min. or more.
4) Check DTC.
Troubleshooting
Step Action YES NO
1
Was A/T System Check performed?
Go to Step 2.
Go to A/T System Check .
2
Check DTC
1) Connect scan tool to DLC with ignition switch turned OFF.
2) Check DTC for ECM and TCM.
Is there any DTC(s) (other than DTC P1674, P1675, P1676 for ECM and DTC P1774, P1775, P1777 for TCM)?
Go to applicable DTC diag. flow.
Go to Step 3.
3
Check CAN Communication Error for TCM
1) Check DTC for TCM.
Is there DTC P1774?
Go to DTC P1774 (No.76): Control Module Communication Bus Off (M13A Model with VVT) .
Go to Step 4.
4
Check ECM and TCM Connectors
1) Check for proper connection at each ECM and TCM connector terminals with ignition switch turned OFF.
2) If connections are OK, recheck DTC for TCM with engine running.
Is there DTC P1777?
Go to Step 5.
Intermittent trouble. Check for intermittent referring to Intermittent and Poor Connection Inspection .
5
Check TCM Power and Ground Circuit
1) Check for TCM power and ground circuit referring to TCM Power and Ground Circuit Check .
Is it in good condition?
Go to Step 6.
Repair TCM power and/or ground circuits.
6
Check DTC for ECM
1) Check DTC P1674 for ECM.
Is it indicated?
Go to DTC P1674: CAN Communication (Bus Off Error):M13A with VVT .
Go to Step 7.
7
Check CAN Communication Line Circuit Continuity
1) Disconnect connectors from ECM and TCM with ignition switch turned OFF.
2) Measure resistance at the following connector terminals.
• Between “E121-7” terminal of TCM connector and “E118-7” terminal of ECM connector
• Between “E121-17” terminal of TCM connector and “E118-8” terminal of ECM connector
Is each resistance below 1 Ω?
Go to Step 8.
Repair open or high resistance of CAN communication line circuit referring to Precaution for CAN Communication System .
8
Check CAN Communication Line Circuit Insulation
1) Measure resistance between “E121-7” and “E121-17” terminals of TCM connector.
Is resistance infinity?
Go to Step 9.
Repair insulation of CAN communication line circuit referring to Precaution for CAN Communication System .
9
Check CAN Communication Line Circuit Ground Short
1) Measure resistance at the following connector terminals.
• Between “E121-7” terminal of TCM connector and vehicle body ground
• Between “E121-17” terminal of TCM connector and vehicle body ground
Is each resistance infinity?
Go to Step 10.
Repair shorted to ground of CAN communication line circuit referring to Precaution for CAN Communication System .
10
Check CAN Communication Line Circuit Power Supply Short
1) Measure voltage at the following connector terminals with ignition switch turned ON.
• Between “E121-7” terminal of TCM connector and vehicle body ground
• Between “E121-17” terminal of TCM connector and vehicle body ground
Is each voltage 0 – 1 V?
Substitute a known-good TCM and recheck. If DTC is still detected, substitute a known-good ECM and recheck.
Repair shorted to power supply of CAN communication line circuit referring to Precaution for CAN Communication System .