20 Most Recent 2004 Volvo S40 Questions & Answers

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.

Hope this helps; also keep in mind that your feedback is important and I`ll appreciate your time and consideration if you leave some testimonial comment about this answer.

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2004 Volvo S40 | Answered on Sep 28, 2019

When was the last time you changed fluids in your transmission, if never it could be that!? Good Luck Steve

2004 Volvo S40 | Answered on Jan 14, 2018

Cannot figure out what that part is, but it has a vacuum line connected. Therefore, it should not be functioning unless the engine is running. I would have to guess there is a wire crossed in the key cylinder. The presence of the key should activate the warning system and perhaps deactivate the security system. However, the engine system wiring comes in proximity to the warning wiring behind the ignition switch near the contact reel. It's possible you have a short in that area. I am posting access instructions from autozone.com.
CAUTION Models equipped with a Supplemental Restraint System (SRS), use an inflatable air bag. Whenever working near any of the SRS components, such as the impact sensors, the air bag module, steering column, and instrument panel, disable the SRS.

  1. Before servicing the vehicle, refer to the Precautions Section.
  2. Disconnect battery cable.
  3. Remove steering wheel and air bag module. Refer to Steering Wheel removal and installation.
  4. Remove steering column covers. Remove or disconnect the following:

    Screws from lower coverClip mounting between the upper and lower coversLower steering column coverUpper steering column cover
  5. Remove the contact reel:
    1. Disconnect the left connector.
    2. Remove the screws.
    3. Remove the contact reel.

      Fig. Removing the contact reel from steering column
      Removing the contact reel from steering column
  6. Remove the ignition switch:
    1. Disconnect the electrical connector.
    2. Remove the screws.
    3. Remove the ignition switch.

      Fig. Ignition switch removal
      Ignition switch removal
To install:
  1. Install the ignition switch:
    1. Position the ignition switch and tighten the screws.
    2. Connect the electrical connector.
  2. Install the contact reel. Tighten the M5 screws to 44 inch lbs. (5 Nm).
  3. Install the upper and lower steering column covers. Tighten the screws.
  4. Install the air bag and steering wheel. Refer to Steering Wheel removal and installation.
  5. Connect the negative battery cable.



2004 Volvo S40 | Answered on Jul 15, 2017

If we're talking about an automatic transmission, your symptoms indicate a valve body problem. The transmission control module or a shift solenoid inside the transmission can be faulty too.

2004 Volvo S40 | Answered on Dec 06, 2016

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

2004 Volvo S40 | Answered on Nov 23, 2016

There is a fuse for these. Fuse good and has power to it. Look at replacing the light/dimmer switch. If the fuse is good, you need to check for power at the switch plug. Could be a bad wire.. Power or ground.

2004 Volvo S40 | Answered on Sep 03, 2016

You need to have ignition switch in the on position for two uninterrupted hours or two hours driving around with the radio turned on. It will say "OFF" on display. Once you do this you should be able to enter your code.

2004 Volvo S40 | Answered on Sep 03, 2016

Most have a recessed allen screw, or star-key nut located on the back side of the knob...some are hidden by a clip on cover...look for at the base of the knob design...

2004 Volvo S40 | Answered on Nov 10, 2015

There could be various reasons why it is being set off. It could be a faulty shock sensor, or you could have a battery drain while car is off. Alarms check for voltage changes while engaged. (That would mean you have an electrical problem) . the battery voltage may be too low. (Or a bad battery/charging circuit)or the alarm itself is malfunctiong.

2004 Volvo S40 | Answered on Sep 16, 2015

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