P0149 Fuel Timing Error
OBD-II Trouble Code Technical Description
Fuel Timing Error
What does that mean?
This diagnostic trouble code (DTC) is a generic powertrain code, which means that it applies to OBD-II equipped vehicles (Dodge, Ram, Ford, GMC, Chevrolet, VW, Audi, etc.). Although generic, the specific repair steps may vary depending on make/model.
If your OBD II equipped vehicle has presented a code P0149, it means that the powertrain control module (PCM) has detected a malfunction in the timing sequence of the fuel pump. I have never seen this code exhibited in a vehicle that was not propelled by a diesel engine.
Most of today’s clean burning, direct injection, diesel engines utilize a mechanical fuel pump that is driven directly off the crankshaft. In order to overcome the high compression ratios associated with diesel engines, this type of pump is timed in sequence with the position of the crankshaft to provide a high pressure injection pulse (up to 44,000 psi) at a precise point and interval, for each cylinder of the engine. The fuel pump is typically small enough to fit underneath the intake manifold and has the low pressure pump, the high pressure pump, the fuel timing solenoid, and the fuel pressure control actuator integrated within. There will likely be a fuel pressure sensor nearby as well.
The fuel pump is pulsed using a toothed sprocket which is aligned with a toothed sprocket on the front of the crankshaft. Timing of the two sprockets (using a steel chain) is critical to fuel pump timing and fuel delivery. If the two sprockets are misaligned by even a single tooth, a code P0149 may be stored.
The PCM uses inputs related to engine RPM and engine load to calculate fuel timing advance. The electronic fuel timing solenoid is controlled by the PCM and allows direct injection timing to be advanced according to engine speed and load.
The electronic fuel pressure regulator is also controlled by the PCM and is responsible for controlling fuel pump pressure. The fuel pressure sensor monitors fuel pressure, with the engine running, and provides the PCM with an actual reading so that it can continue to plot fuel pump timing and monitor fuel pressure requirements. If the PCM detects a fuel pressure input signal, indicating that there is a problem with fuel pump timing, a code P0149 will be stored and a malfunction indicator lamp may be illuminated.
NOTE: Please use extreme caution when attempting to service the high pressure fuel system. This type of system should be serviced only by trained personnel. Consult a reliable vehicle information source (such as All Data DIY) for more precautions.
Code Severity & Symptoms
Assuming that the vehicle will start, inconsistencies in fuel pump timing can result in engine damage. A stored code P0149 should be considered severe.
Symptoms of a P0149 code may include:
Causes
Potential causes for this code to set are:
Diagnostic and Repair Procedures
A good starting point is always to check for technical service bulletins (TSB) for your particular vehicle. Your issue may be a known issue with a known fix put out by the manufacturer and can save you time and money during diagnosis.
Although a stored code P0149 may be caused by either a mechanical failure or an electrical issue, mechanical failure is not likely unless recent related repairs have been performed. If the engine and/or the high pressure fuel pump have recently been re-timed, definitely suspect that a misalignment of the corresponding timing marks has taken place and caused this code to be stored.
Barring a mechanical glitch, you will need a diagnostic scanner, a digital volt/ohmmeter (DVOM), and a vehicle information source like All Data DIY to diagnose a code P0149.
Retrieve all stored codes and freeze frame data by connecting the scanner to the vehicle diagnostic connector. Write this information down just in case you need it later, then clear the codes and proceed.
If there is an intense fuel odor, suspect that a fuel leak is at the root of your problem. Fuel system components which have been recently replaced should be carefully inspected if a fuel leak is detected. Once you have performed a visual inspection of all fuel delivery lines and components, repair leaks as necessary and retest the system to see if the code is reset.
Test the fuel pressure sensor, fuel control actuator, and the fuel timing solenoid as recommended in your vehicle information source, using the DVOM. Replace components which fail to meet manufacturer’s recommended specifications and retest the system.
If you continue to have issues, use your vehicle information source to search technical service bulletins (TSB) for one that matches your specific vehicle, symptoms, and code/s. The information contained therein may help you to pinpoint the malfunction and rectify the situation.
Additional diagnostic notes:
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"Delete Error Code Permanently, Disable DTC Error Code Function for p0149 in the ECU"
In extreme cases, we even have the option to permanently remove the specific DTC p0149 and disable the function of the specific error code in the ECU. All other fault code functions will then continue to work to protect the engine. This is different from clearing an error code with a diagnostic device. We have the option to permanently remove the function of the specific error code, so that it never comes back. Also emergency running that occurs on the specific error code can be solved in most cases.
Of course we prefer to first try to solve the cause of the error code, but sometimes the only solution is to permanently disable the DTC function of p0149.
