How to Reset Mazda MPV Check Engine Lightsby Jody L. Campbell
The Mazda MPV was introduced in 1989. It has featured two types of powertrain control modules in the onboard diagnostic (OBD) phase. For earlier versions of the MPV prior to the implementation of OBD II in 1996, the procedure to reset the check engine light is different than later versions of the vehicle. Nowadays, OBD II scanners are quite affordable and can erase the codes without disrupting the stored information the battery provides to the powertrain control module. Most auto parts stores or repair stations will even scan or reset your codes for free as long as the proper repairs have been made to fix the problem.
OBD I: 1989-1995 Mazda MPVs
Open the hood to the Mazda MPV and disconnect the negative terminal clamp from the battery. Loosen the retaining bolt with a hand wrench until you can wiggle the clamp off of the battery post.
Go to the driver's seat and insert the keys in the ignition.
Turn the ignition to the accessory power position (two clicks forward) and then turn on the headlight switch. This will purge any stored reserve power from the battery connection to the powertrain control module.
Turn the headlight switch off and then turn the ignition key to the off position and remove the keys.
Wait 10 minutes and reconnect the negative battery terminal clamp. Tighten the clamp's retaining bolt with the hand wrench until the clamp is secure against the battery post.
Start the engine and check the instrument panel to ensure the check engine light is out.
OBD II: 1996 and Newer Mazda MPVs
Locate the data link connector (DLC) outlet beneath the steering column on the MPV. On later versions of the MPV, the DLC is slightly to the left of the steering column.
Plug the OBD II pocket scanner into the DLC.
Turn the ignition key to the accessory power position (two clicks forward) and then follow the onscreen menu of the scanner. There are some scanners that feature an "erase" button. On scanners with an "erase" button, simply press the button. Other scanners will require scrolling through the menu to choose the erase code or erase DTC (diagnostic trouble codes) option.
Press the "send," "erase" or "enter" button to reset the powertrain control module. Wait for the scanner to instruct you that the command has been sent or the main menu reappears.
Turn the engine on to ensure the check engine light is no longer illuminated on the instrument panel.
- While disconnecting the negative battery terminal will reset the check engine light, it is not recommended on OBD II systems that feature theft-deterrent radios and internal alarm systems. Doing so will erase operational codes for both, and the systems will have to be reprogrammed to allow the MPV to start and for the radio to work.
- Resetting the check engine light in the Mazda MPV should only be performed after the DTC has been properly diagnosed and the repair has been made to resolve the problem that triggered the DTC. Simply resetting the light is not fixing the problem and in some cases, the check engine light will come back on. In addition, if the triggered DTC is a hard code, the check engine light will re-illuminate almost immediately. In other cases, the light will come back on after the powertrain control module has relearned and recommunicated with the sensors and modules connected to it. Failure to fix the problem can lead to severe engine or transmission damage or compromise components in the emissions system. Resetting the check engine light will not allow the MPV to sneak through state inspections that require emissions testing; even if not illuminated on the dash. The inspection and maintenance monitors (IM monitors) will not be reset and most all onboard computers hooked to the DLC will be able to detect that the powertrain control module is not "ready." As a result, the vehicle will fail emissions testing until the powertrain control module is in its "ready" mode, and, once it is, if the repair hasn't been made, it will retrigger the DLC and the vehicle will still fail.
Jody L. Campbell spent over 15 years as both a manager and an under-car specialist in the automotive repair industry. Prior to that, he managed two different restaurants for over 15 years. Campbell began his professional writing career in 2004 with the publication of his first book.