C3494 Lea-francis 18 code definition:
C3494 is a kind of OBD-II Diagnostic C-Chassis Diagnostic Trouble Code for Lea-francis 18.
C3494 Lea-francis 18 is defined as Knock Sensor Circuit Range Performance (Bank 1 or Single Sensor). This refers to camshaft timing, which in this case is over-retarded. As you drive and when specific conditions are slowly met, the vapors will gradually purge from the charcoal canister and will get burned within your engine.
Symptoms of a C3494 Lea-francis 18 diagnostic trouble code may include:
Faulty or damaged wiring
The engine oil will exhibit dilution from the ECUs attempts to increase engine temperature. Some vehicles advance the fuel injection timing slightly after top center to afterburn a small amount of fuel to increase exhaust temperatures. Some of this fuel enters the crankcase. When the ECU determines the necessity to regenerate the DPF, the service life of the oil be shortened significantly
Poor fuel economy
Reduction in engine performance, especially at low RPM levels
Possible Causes :
A faulty oxygen sensor. This will set a code in itself, however, a faulty oxygen sensor does not automatically condemn the sensor. The code just means that the sensor signal was not within specifications. An air leak or any of the above will cause an erroneous signal. There is a multitude of O2 codes relating to O2 performance which gives a clue to the problematic area.
Some aftermarket accessories and performance modifications
A large vacuum leak would cause a massive amount of un-metered air to enter the intake manifold resulting in an overly lean mixture.
IC Circuit High Voltage Problem
Control Module Throttle Actuator Position Performance Problem
Air Conditioning (A/C) Clutch Feedback Circuit High Voltage Problem
Cruise Vehicle Speed/Set Speed Difference Too High Problem
PCM Stack Overrun Problem
Repair Processes :
Look for missing ground strap or a rusty ground where the fuel tank is grounded to the frame. Check for damage to the wiring harness connector.
You might continue by connecting the scanner to the vehicle diagnostic connector and retrieving all stored codes and freeze frame data.
Diagnostic trouble code C3494 Lea-francis 18 is not difficult to diagnose and repair. Thus, it always pays to have a qualified technician to look after your vehicle should this error code arise.
Diagnosing this code requires the engine to be in good running shape, without unmetered air entering the engine. If other codes that relates to misfiring condition, lean running or air entering the engine is present, then you must first fix those error codes before C3494 Lea-francis 18.
Fortunately, C3494 Lea-francis 18 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.
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