C3994 Ford E-series OBD Code

OBD/2 C3994 error code description and symptoms.

Engine Coolant Temperature (ECT) Circuit High Input Indicates the sensor signal is greater than Self-Test maximum. The ECT sensor maximum is 4.6 volts or -50 C (-58 F). Note on some vehicles that are not equipped with an ECT sensor, CHT can be used and can set this DTC. Open circuit in harness Sensor signal short to power Damaged PCM Improper harness connection Damaged sensor ECT V PID reading greater than 4.6 volts with key ON and engine OFF or during any engine operating mode indicates a hard fault.

As the engine heats up and combustion becomes easier and more complete, the PCM will command the idling control valve to increase the amount of air entering the engine to suit the changing conditions. However, when the load on the engine changes, say, when some electrical consumers or other systems are either turned on or off, the PCM adapts the signal voltage to the idle control valve to ensure that the idling speed remains stable, and at the RPM specified by the manufacturer.

C3994 Ford E-series Error Code Repair Process :

The rule of C3994 code when it comes to emissions-related vehicle repair is that any modification that changes the vehicle from a certified configuration to a non-certified configuration is considered tampering: this applies to both vehicle owners and repair facilities and is, therefore, a Federal offense. Replacing a catalyst with a straight pipe is one traditional example of air suspension rear inflator solenoid output circuit open. Likewise, overriding the OBD C3994 error in system through the use of high-tech defeat devices or non-certified computer chips, for example, would also be considered tampering. The OBD system may, however, be repaired back to its original certified configuration with certified performance chips or appropriate aftermarket parts.

Common Causes of Ford E-series C3994 OBD2 Code

A common cause of code C3994 is the failure of Air Suspension Rear Inflator Solenoid Output Circuit Open, but there are several other possible causes as well, such as ;

Engine Control Module (ECM)
Faulty Air fuel ratio (A/F) Sensor 1 Bank 1
Camshaft advance mechanism binding (VCT unit)
Fuel Injectors circuit poor electrical connection

C3994 is a kind of Chassis Trouble Code

Diagnosing chassis noises can be one of the most frustrating problems technicians face. Fortunately, manufacturers have engineered noise, vibration and harshness (NVH) diagnostic techniques and equipment to find the source of the noise.

Engine OBD 2 Codes website is a freeware resource center for engine trouble codes.

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C3994 Ford E-series OBD Code

C3994 Ford E-series Error Code Repair Process :

Common Causes of Ford E-series C3994 OBD2 Code

C3994 code for other Ford cars