Pinpoint Test C : DTC (Diagnostic Trouble Code) P1780

WARNING: This page is about a different car, the 2017 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.

C1 KOER (KEY ON, ENGINE RUNNING) SELF-TEST

Using a diagnostic scan tool, perform a KOER self-test.

Is the DTC P1780 set?

Yes

GO to C2

No	No trouble found with the Tow/Haul system. If the Tow/Haul or Sport lamp do not illuminate, Refer to: Instrumentation, Message Center and Warning Chimes .

C2 CHECK FOR POWER AT TOW HAUL SWITCH

Ignition OFF.

Disconnect Selector Lever Assembly Column shift, C2135 .

Disconnect Selector Lever Assembly Floor Shift, C3245 .

Ignition ON.

For vehicles equipped with column shift, measure:

Positive Lead	Measurement / Action	Negative Lead
C2135-1	Courtesy of FORD MOTOR COMPANY	Ground

For vehicles equipped with floor shift, measure:

Positive Lead	Measurement / Action	Negative Lead
C3245-6	Courtesy of FORD MOTOR COMPANY	Ground

Is the voltage 11 volts or greater?

Yes

GO to C3

No	VERIFY the BJB fuse 19 (5A) is OK. If OK, REPAIR the open circuit. If not OK, REFER to OEM Electrical Wiring Diagram Introduction to identify the possible causes of the circuit short.

C3 CHECK GROUND CIRCUIT TO PCM

Ignition ON.

For vehicles equipped with column shift, measure:

Positive Lead	Measurement / Action	Negative Lead
C2135-2	Courtesy of FORD MOTOR COMPANY	Ground

For vehicles equipped with floor shift, measure:

Positive Lead	Measurement / Action	Negative Lead
C3245-5	Courtesy of FORD MOTOR COMPANY	Ground

Is the resistance less than 3 ohms?

Yes	INSTALL a new tow/haul switch. Refer to: Selector Lever Knob .

GO to C4

C4 TEST THE GROUND CIRCUIT FOR AN OPEN

Disconnect If equipped with 2.7L engine, PCM C1232B .

Disconnect If equipped with 3.7L TiVCT engine, PCM C1551B .

Disconnect If equipped with 5.0L engine, PCM C1381B .

If equipped with 2.7L engine, measure:

Positive Lead	Measurement / Action	Negative Lead
C1232B-90	Courtesy of FORD MOTOR COMPANY	For vehicles equipped with column shift, C2135-2
C1232B-90	Courtesy of FORD MOTOR COMPANY	For vehicles equipped with column shift, C3245-5

If equipped with 3.7L TiVCT engine, measure:

Positive Lead	Measurement / Action	Negative Lead
C1551B-93	Courtesy of FORD MOTOR COMPANY	For vehicles equipped with column shift, C2135-2
C1551B-93	Courtesy of FORD MOTOR COMPANY	For vehicles equipped with column shift, C3245-5

If equipped with 5.0 engine, measure:

Positive Lead	Measurement / Action	Negative Lead
C1381B-93	Courtesy of FORD MOTOR COMPANY	For vehicles equipped with column shift, C2135-2
C1381B-93	Courtesy of FORD MOTOR COMPANY	For vehicles equipped with column shift, C3245-5

Is the resistance less than 3 ohms?

Yes

INSTALL a new PCM REFER to: Powertrain Control Module (PCM) - 2.7L EcoBoost . Refer to: Powertrain Control Module (PCM) - 3.5L Duratec . Refer to: Powertrain Control Module (PCM) - 3.5L EcoBoost . Refer to: Powertrain Control Module (PCM) - 5.0L 32V Ti-VCT . PERFORM the Transmission Strategy Download procedure. REFER to: Transmission Strategy Download - 6-Speed Automatic Transmission - 6R80 .

No	REPAIR the circuit.