Incorrect fuel reading. Show different levels of fuel. Needle goes back and forth. 2004 Volvo S40

If plans a fail,plan B drive 300 km. and fill up.

Hi James,
The most likely cause is the fuel sending unit. When they go bad, you start getting erratic readings. Hope that helps.

pump is in the tank.. also check the fuel filter too..

Sound like a problem with the MAF sensor, try replace.

Pulled codes for ECM-250A long term fuel trim upper limit, inspected and found air mass sensor failing internally, should show 4 f/s at idle and is showing 2.98 f/s at idle. Recommend replacing with new.



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The tank will need to be removed and the float or sensor repaired.

IT GOES IN AT THE REAR SIDE PANEL.

If the display says "Off" the radio is locked from incorrect code input.

You need to leave the key in the accessory position with the radio on (display reads 'Off') for about two hours.
After that it should ask for he code again. You have three tries before it locks again.
Some radios are different, but typically you use the knob to adjust the numbers, push the knob in to move to the next number

Each radio has a different code. You need to call a Volvo dealership and read them the vin number and they can pull the code up for you

check your mass meter and air filter