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Home >> Ford >> 2018 >> Mustang GT, Automatic Trans >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 2 (Electronic Engine Controls - 5.2L 32V Ti-VCT) >> Diagnosis And Testing >> Electronic Engine Controls >> Pinpoint Tests >> Pinpoint Test D : Tailpipe Actuator Faults >> Notes

Pinpoint Test D : Tailpipe Actuator Faults: Notes

WARNING: This page is about a different variant/trim than selected.

Refer to Electronic Engine Controls - 5.2L for schematic and connector information.

DTC Fault Trigger Condition-PCM 

DTC Description Fault Trigger Conditions
P26C5 Exhaust Flow Control Valve "A" Control Circuit/Open This DTC sets when an open is detected on the tailpipe actuator circuit.
P26C6 Exhaust Flow Control Valve "A" Control Circuit Low This DTC sets when a short to ground is detected on the tailpipe actuator circuit.
P26C7 Exhaust Flow Control Valve "A" Control Circuit High This DTC sets when a short to voltage is detected on the tailpipe actuator circuit.
P26FE Exhaust Flow Control Valve "A" Control Performance This DTC sets when the LH or RH tailpipe actuator is stuck in the open, closed or in an unknown position. The PCM cannot determine which valve is reporting the concern.

Normal Operation and Fault Conditions 

There is a LH and RH tailpipe actuator on both inboard muffler outlet pipes. The PCM uses a shared PWM circuit to control the operation of both tailpipe actuators. With the vehicle drive mode in normal mode  with the engine running, the actuators are fully closed. The PCM fully opens the actuators based on engine load, engine RPM and vehicle speed. During normal operation the actuators are either fully open or fully closed, never in a partially open position. Putting the vehicle drive mode into Sport mode  forces the actuators to stay at full open. Refer to the Owner's Literature for more information. The valve position can be verified by looking into the inboard muffler outlet pipes. The tailpipe actuator shorts the PWM control circuit to ground for a specific period of time if a fault is detected. The duration changes depending on the fault:

Tailpipe Actuator Fault Duration of Short to Ground
Stuck closed 1 second
Unknown position 1.5 seconds
Stuck open 2 seconds

SELF-TEST 

With the ignition OFF and the PCM in sleep mode the tailpipe actuators perform a self-test when the clutch pedal or the engine start/stop button is pressed. This self-test may take up to 9 minutes to be performed. During the self-test, the tailpipe actuators fully open and close twice. If the clutch pedal and engine start/stop button are pressed simultaneously, the engine starts and may sound like it is revving without a corresponding engine RPM change, this is normal operation.

Possible Sources 

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