Worn or stretched timing chain or belt, causing the camshaft to drift out of sync with the crankshaft; Faulty camshaft position sensor or crankshaft position sensor, sending erratic signals to the PCM; Damaged or corroded wiring or connectors in the camshaft or crankshaft sensor circuits; A failing variable camshaft timing (VCT) solenoid or phaser, disrupting the camshaft's commanded position; Contaminated or low engine oil affecting VCT operation and sensor performance; PCM software issue or internal fault, though this is less common

DTC codes / Ford codes / P1177

P1177 · FordSynchronization Fault

Q: What does code P1177 mean?

Synchronization Fault. P1177 on Ford vehicles indicates a synchronization fault between the camshaft and crankshaft signals, meaning the powertrain control module (PCM) has detected a mismatch in the expected timing relationship. The PCM monitors these signals to ensure the engine's valve and piston motion stay coordinated, and this code sets when the correlation falls outside the allowed window.

P1177 on Ford vehicles indicates a synchronization fault between the camshaft and crankshaft signals, meaning the powertrain control module (PCM) has detected a mismatch in the expected timing relationship. The PCM monitors these signals to ensure the engine's valve and piston motion stay coordinated, and this code sets when the correlation falls outside the allowed window.

SystemPowertrain

Code typeFord specific

SeverityHigh

Fix difficultyProfessional

AreaFuel and air metering

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms
Rough idle or stumbling, especially when the engine is cold
Engine misfire or hesitation during acceleration
Hard starting or extended cranking before the engine fires
Reduced engine power or limp mode in some cases
Poor fuel economy or increased emissions

Common causes, most likely first

Worn or stretched timing chain or belt, causing the camshaft to drift out of sync with the crankshaft
Faulty camshaft position sensor or crankshaft position sensor, sending erratic signals to the PCM
Damaged or corroded wiring or connectors in the camshaft or crankshaft sensor circuits
A failing variable camshaft timing (VCT) solenoid or phaser, disrupting the camshaft's commanded position
Contaminated or low engine oil affecting VCT operation and sensor performance
PCM software issue or internal fault, though this is less common

How to diagnose and fix it

Use a scan tool to retrieve all stored codes and freeze-frame data, then verify the P1177 is current and not history
Inspect the camshaft and crankshaft sensor wiring and connectors for damage, corrosion, or loose pins
Check engine oil level and condition, and perform an oil and filter change if the oil is dirty or the level is incorrect
Test the camshaft and crankshaft position sensors with a multimeter or oscilloscope to confirm signal integrity
Verify timing chain or belt alignment using factory procedures, looking for stretch or skipped teeth
Test the VCT solenoid for proper operation and clean or replace it if sticking or clogged
If all else fails, reflash or replace the PCM after confirming no other faults exist

Before you replace the timing chain

A stretched timing chain is a common cause on high-mileage Ford engines, but always rule out sensor and wiring faults first because they are cheaper and easier to fix.
Dirty engine oil can clog VCT solenoids and cause synchronization faults, so regular oil changes with the correct viscosity are critical on Ford VCT engines.
The P1177 code can sometimes be set by a weak battery or charging system issue that causes voltage spikes and disrupts sensor signals.
After replacing timing components, the PCM may need a relearn procedure or a drive cycle to clear the code and confirm the repair.
Do not ignore this code, as prolonged driving with a synchronization fault can lead to severe engine damage if the timing chain fails completely.

Can I keep driving with P1177?

It is not safe to continue driving with a P1177 code because a synchronization fault can lead to sudden engine stall or catastrophic timing chain failure. Have the vehicle towed to a repair shop for diagnosis and repair.

Tools that help

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Guidance is general and written for Ford vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.