DTC Troubleshooting

DTC P1779 TROUBLESHOOTING CHART

Step	Action	Value(s)	Yes	No
1	Perform an On-Board Diagnostic (OBD II) System Check. Is the check completed?	-	Go to Step 2.	Go to "ON-BOARD DIAGNOSTIC (OBD II) SYSTEM CHECK ".
2	Install the scan tool. Turn the ignition ON. Observe the throttle position value on the scan tool. Is the TPS within the values shown?	0 - 100%	Go to "DIAGNOSTIC AIDS ".	Go to Step 3.
3	Turn the ignition OFF. Disconnect the TCM wiring connector and ECM wiring connector. Measure the resistance between terminal A8 of the TCM wiring connector and terminal 41 of the ECM wiring connector. Measure the resistance between terminal A16 of the TCM wiring connector and terminal 22 of the ECM wiring connector. Is the resistance within the values shown?	= 0 Ω	Go to Step 5.	Go to Step 4.
4	Repair the malfunctioning terminals as necessary. Is the action complete?	-	System OK	-
5	Turn the ignition ON. Measure the voltage of terminal A8. Measure the voltage of terminal A16. Is the voltage within the values shown?	11 - 14V	Go to Step 6.	Go to Step 7.
6	Repair the short to power on the terminal(s) as necessary. Is the action complete?	-	System OK	-
7	Replace the TCM. Turn the ignition OFF. Turn the ignition ON. Check if P1779 DTC is set. Is The DTC set?	-	Go to Step 8.	Go to Step 9.
8	Replace the ECM. Is the action complete?	-	Go to Step 9.	-
9	After the repair, use a scan tool "clear info" function and road test the vehicle. Review the "DTC info". Has the last test failed or is the current DTC displayed?	-	Begin diagnosis again.	Repair verified exit DTC chart.