Possible fuel pump issue - Need some advice

[Luke Clifton]

Hi there.

I have a A3 S-Line 2010. This week it had to be recovered due to stalling and then not starting again while driving. Battery and alternator are ok.

When i turn on the ignition i don't hear any fuel pump sound. Think i may be the fuel pump? Checked the fuse and its ok.

I have some ODB codes but i'm not sure if these would cause the engine not to start? 

P0100 - Mass or Volume Air Flow - A Circuit
P2015 - Intake Manifold Runner - Position Sensor / Switch - Circuit Range / Performance Bank1a

Can anyone provide some insight as to whether these error codes are a separate issue or related to the engine not starting?

Thanks,

Luke

[Steve Q]

Welcome to the forum alike, you'll find the members on here are a friendly and helpful bunch 🙂

The first code would indicate ba fault with the MAF (mass air flow) sensor. The sensor is located near to the airbox. 

The second code indicates an issue with the Intake Manifold Runner Position Sensor Range Bank 1.

The intake manifold sits on top of the engine between the cylinder heads. Runners inside the manifold deliver air to the engine via a series of runners. Many modern vehicles use what’s called an intake manifold runner control (IMRC) system. This system varies the manifold runner length by opening and closing a series of valves. This allows for fine-tuning of the engine’s air intake, resulting in better performance and fuel economy. The valves are controlled either by a vacuum solenoid or electric actuator.

Code P2015 is typically caused by one of the following:

• A failed intake manifold position sensor
• A failed IMRC actuator/solenoid
• A problem with the intake manifold or linkage
• Wiring problems

How to diagnose and repair P2015

Perform a preliminary inspection

Sometimes P2015 can pop up in error. Clear the code and see if it returns. If it does, the next step is to perform a visual inspection. A trained eye can check for issues such as broken wires and loose connections. If a problem is found, it should be repaired and the code cleared. If nothing is discovered, check for technical service bulletins (TSBs). TSBs are recommended diagnostic and repair procedures put out by the vehicle manufacturer. Finding a related TSB can greatly reduce diagnostic time.

Check the IMRC operation

A technician will typically begin diagnosis of this code by monitoring IMRC system operation on a scan tool. When connected to the vehicle’s diagnostic port, the scan tool can communicate with onboard modules. The IMRC valves can be opened and closed with the scan tool with the push of a button. Data is also displayed on the scan tool regarding IMCR operation. This allows a technician to manually operate the valves while monitoring the data to so if the system is working properly.

Check the IMRC circuit

Once it’s confirmed the IMRC system is not working correctly, the reason why must be determined. A technician will start by testing the IMRC circuit. A digital multimeter (DMM) can be used to ensure both the sensor and actuator/solenoid circuits are intact.

If a problem is found in the circuit, the factory wiring diagram will need to be traced. Then, once the problem area has been located, the open/short circuit can be repaired.

Check the intake manifold and linkage

The next step is to check the mechanical portion of the IMRC system. Some IMRC systems use manifold vacuum to open and close the runner valves, while others use mechanical linkage.

• Operate the mechanical linkage by hand to check for proper operation. If it binds or doesn’t open the valves, the linkage or manifold should be replaced.
• With a vacuum controlled system, the runner valves can be opened and closed with a handheld vacuum pump. The pump is connected to the intake manifold. If the valves don’t operate as designed during this test, the manifold is probably defective.

In both cases, the intake manifold may need to be removed to verify the runner valves are opening and closing properly.

Either of these issues can cause rough running or poor fuel economy. Have you experienced either of those issues? Obviously if the car gets starved of air then it'll stall it might be worth getting these two faults repaired first maybe. 

cheers

Steve