P1600

DTC P1600: Serial Communication Problem Between ECM and TCM

Wiring Diagram










Circuit Description

The serial data line is pulled up to about 5 V by ECM and TCM transmits information to ECM through it by controlling its grounding.

TCM constantly sends information while ignition switch is ON as to whether judgement was made or not with respect to all detectable DTCs as well as whether or not abnormality exists after judgement.

DTC Detecting Condition and Trouble Area






DTC Confirmation Procedure

NOTE:

Check to make sure that the following conditions are satisfied when using this DTC confirmation procedure.

- Intake air temp.: -14 °C, 6.8 °F or higher
- Altitude (barometric pressure): 2020 m, 6650 ft or less (540 mmHg, 72 kPa or more)

1) Connect scan tool to DLC with ignition switch turned OFF.
2) Turn ON ignition switch and clear DTC using scan tool.
3) Start engine and run it at idle for 5 min. or more.
4) Check DTC and pending DTC.

DTC Troubleshooting

1.
Was "Engine System Check" performed?
YES
Go to Step 2.
NO
Go to Engine System Check Engine System Check.

2. Signal voltage check.

Disconnect connectors from ECM with ignition switch turned OFF.
Remove ECM from vehicle body and then connect connectors to ECM.
Start engine and then check voltage between terminal "G04-31" and body ground with ignition switch ON.

Does voltage repeat 0 - 1.5 V and 10 - 14 V?
YES
Intermittent trouble or faulty ECM or TCM.
Check for intermittent trouble referring to Intermittent and Poor Connection Inspection.
NO
Go to Step 3.

3. Signal circuit check.

Disconnect connectors from TCM with ignition switch turned OFF.
Disconnect connector from ECM.
Check that there is insulation between "G04-31" terminal and vehicle body ground.

Is there insulation?
YES
Go to Step 4.
NO
"GRN/YEL" wire shorted to ground or other circuit.

4. Signal circuit check.

Turn ON ignition switch.
Measure voltage between "G04-31" terminal and vehicle body ground.

Is voltage 0 V?
YES
Go to Step 5.
NO
"GRN/YEL" wire shorted to power supply or other circuit.

5. Signal circuit check.

Measure resistance between "G04-31" terminal in ECM harness connector and "G07-27" terminal in TCM harness connector.

Is resistance below 3 ohms?
YES
Go to Step 6.
NO
"GRN/YEL" wire in open or high resistance circuit.

6. Signal circuit check.

Connect connectors to ECM with ignition switch turned OFF.
Measure voltage between "G04-31" terminal and vehicle body ground.

Dose voltage repeat 0 - 1.5 and 10 - 14 V?
YES
Faulty TCM.
Substitute a known-good TCM and recheck.
NO
Faulty TCM.
Substitute a known-good TCM and recheck.