P00F4 Humber 20 Diagnostic Trouble Code

P00F4 Humber 20 code definition:
P00F4 is a kind of OBD-II Diagnostic P-Powertrain Diagnostic Trouble Code for Humber 20.

P00F4 Humber 20 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. This is because the barometric pressure sensor is part of the MAF sensor. Sometimes, the MAF's sensing wire can accumulate and get covered with dirt, dust and/or oil residue, which can also lead to the error code.

Symptoms

Symptoms of a P00F4 Humber 20 diagnostic trouble code may include:

Blown fuse (if applicable)
Engine surge
Reduction in engine performance, especially at low RPM levels
Diminished fuel efficiency

Possible Causes :

The Mass Airflow sensor is a hot wire that senses the volume of air entering the intake manifold. The computer uses this information to control fuel mixture.
Defective ECU strategies or components will prevent proper regeneration
Dirty air cleaner element Damaged DPF

Common Misdiagnoses

Crankshaft Position Sensor Circuit Performance Problem
TP Sensor Learn Not Complete Problem
Low Coolant Circuit Problem
Cruise Control System - Vehicle Accel Too High Problem
Kick-Down Switch Failed Short Problem

Repair Processes :

Look at the plug wires to make sure they are not burnt or laying on the exhaust. With the valve disconnected, the red voltmeter lead should be attached to the IMRC valve power wire and the black voltmeter lead connected to ground. Now, clear the codes and test-drive the vehicle to see if the code is reset.

Process Tips

Diagnostic trouble code P00F4 Humber 20 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 P00F4 Humber 20.

Fortunately, P00F4 Humber 20 is a fairly common OBD code, meaning that it applies to all makes and models of vehicles made after 1996.