Starting System Fault, car engine won't turn over by it's push start button

CARLOS MARIO ARIZA RAGA

MEMBER
2017 FORD MUSTANG
5.2L
V8
2WD
MANUAL
31,000 MILES

Hi, My Vehicle is a 2017 Ford Mustang Shelby GT350 5.2L

Codes: U016C p0192 p0182, I already did testing as asked to do by fords repair manual for the codes, for example: for code u016c I did the following:

with Ignition OFF.
For DTCs P027B or U016C,
Fuel Pump Control Module 2 Module connector disconnected.
Ignition ON, engine OFF.
Measure the voltage between:
(+) Fuel Pump Control Module 2 Module Connector, Harness Side
(-)
VPWR Fuel - Pin 1
Ground

Measure the voltage between:
(+) Fuel Pump Control Module Connector, Harness Side
(-)
VPWR Fuel
Ground
Is the voltage greater than 10.5 V?
this tested yes! Giving 11 volts constant

if yes go to kc3

- KC3 CHECK THE GND CIRCUIT FOR AN OPEN
Ignition OFF.
For DTCs P027B or U016C,
Measure the resistance between:
(+) Fuel Pump Control Module 2 Module Connector, Harness Side
(-)
GND - Pin 4
Ground

Is the resistance less than 5 ohms?
Yes it has 2 ohms

if yes GO to KC4.

KC4 CHECK THE FPC AND FPM CIRCUITS FOR AN OPEN
PCM connector disconnected.
For DTCs P027B or U016C,
Measure the resistance between:
(+) Fuel Pump Control Module 2 Module Connector, HarnessSide
(-) PCM Connector, HarnessSide
FPC - Pin 3

FPM2 - Pin 7

Are the resistances less than 5 ohms?
yes, its 2 ohms

if yes go to step kc5 and on this next step is where I find an issue. It says.

KC5 CHECK THE FPC AND FPM CIRCUITS FOR A SHORT TO GROUND
For DTCs P027B or U016C,
Measure the resistance between:
(+) Fuel Pump Control Module 2 Module Connector, Harness Side
(-)
FPC - Pin 3
Ground
FPM2 - Pin 7
Ground

Are the resistances greater than 10K ohms?
Yes?
GO to
KC6

NO?
REPAIR the short circuit. Clear the PCM DTCs.
REPEAT the self-test.

so in this test when doing as instructed here, I do not receive any measurement on my multimeter, it's like if there's an open or something, i'm not sure. (It's not the multimeter, I tested the same procedure on another mustang just like mine and this part of the test does pass and the car works fine)

can you advise from here and on? I'm not sure what to do, it says repair the short circuit but I already inspected the harness and nothing is wrong with it. Any suggestions? Please lmk.

NOW, For code: p0192 which essentially are the same troubleshooting procedures but on a 5v circuit, everything tests out just fine until I get to the step where it asks the same as before:

STEP - DD10 CHECK THE FRP CIRCUIT FOR A SHORT TO GROUND
For Mustang 5.2L,
Measure the resistance between:
(+) FRPT Sensor Connector, Harness Side
(-)
FRP
Ground
Is the resistance greater than 10K ohms?
Yes? - GO to DD11

NO? - REPAIR the short circuit. Clear the PCM DTCs. REPEAT the self-test.

please help me, i'm not sure what to do from here, just like on the test above it doesn't get any reading.

For CODE: p0182 same procedure as above on the same 5v circuit, it doesn't pass where it asks:

DD15 CHECK THE FRT CIRCUIT FOR A SHORT TO GROUND
Measure the resistance between:
(+) FRPT Sensor Connector, Harness Side
(-)
FRT
Ground
Is the resistance greater than 10K ohms?
Yes? GO to
DD16

No? REPAIR the short circuit. Clear the PCM DTCs. REPEAT the self-test.

doesn't pass here either, no measurement shows on multimeter just like above.

i already also checked the grounds on the car by hooking positive lead of the multimeter to battery and touching engine block it measures same voltage as on battery and also tried in ground cables and it measures fine, also tried with the ignition on and the same, just fine. I need some guidance from here and on, hope you guys can help! Thank you very much.

1 Reply

4DRTOM

MECHANIC
467 POSTS

Hello,

I see you've gone through alot with this so far usually its the simple thing that gets over looked. In that making sure that the clutch switch, brake switch and the anti theft ID key aren't causing your no start condition or the ignition button itself or the starter solenoid. What was the situation when this first began? Just one day you went to start it and it didn't start clear out of the blue? Does the remote start system work? I would work my way backwards and get right to the starter and jump it there, then get to the starter relay and jump its terminals to see if its good there.
Here is the description of your system and I have attached the signal flow chart too. Review this and let me know if it helps as well as going right to the starter and its relay making sure they are good by starting the car from them.
Push button starting vehicle is equipped with a PATS that disables the engine from cranking if an unprogrammed PATS key is used or an invalid PCM ID is received. The PATS is controlled by the BCM. If there is a PATS concern that causes the engine to be disabled, the IPC displays the corresponding message in the message center. Ignition modes are controlled by the RFA module and the BCM.
The ignition switch - push button start is connected to the RFA module and the BCM as a backup in case of a failure. If there is a circuit failure to either module from the ignition switch - push button start, the modules communicate the ignition switch - push button start request to each other over the Medium Speed Controller Area Network (MS-CAN).
During a start event the ignition switch - push button start is pressed in combination with either the brake pedal (automatic transmission) or the clutch pedal (manual transmission) input. The RFA module, the BCM and the PCM receive a request to start the engine. The PCM recognizes the correct inputs and provides voltage and ground to energize the starter relay coil and close the starter relay contacts. The starter relay contacts close, providing voltage to the starter solenoid, allowing the starter motor to crank the engine. The PCM disengages the starter motor once an engine Revolutions Per Minute (RPM) threshold is reached, a set crank time is exceeded or the ignition switch - push button start is pressed indicating an engine shutdown.

Let us know,
Tom

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