How to Reset the CE (MIL) Light?

[Pro40Dually]

I have a question on the Check Engine Light (MIL). If the problem gets fixed (i.e. change the gas cap for example on a code P0442), will the light go out if the problem is fixed? Or does the ECM need resetting? If so, how do you reset the light?

It figures my truck with 36,179 miles and 1.5 months over the 36 months warranty has a problem.

I'll start by changing the cap and then maybe the filler pipe before having
the dealer look at it.

[LGL002]

Originally Posted by Pro40Dually

I have a question on the Check Engine Light (MIL). If the problem gets fixed (i.e. change the gas cap for example on a code P0442), will the light go out if the problem is fixed? Or does the ECM need resetting? If so, how do you reset the light?

It figures my truck with 36,179 miles and 1.5 months over the 36 months warranty has a problem.

I'll start by changing the cap and then maybe the filler pipe before having
the dealer look at it.

Disconnect the battery for 30 minutes to reset. AutoZone or another large parts store should be able to reset the ECU with their scan tool also.

Larry

[The Phoenix]

If you want the light to disappear immediately, disconnect negative terminal on battery for 5 mins and reconnect and it will be gone... you could also pull the computer fuse but sometimes that won't turn the light off. The light would probably go off on its own after sometime, but there is no way of telling how long. Just reset it manually

[Pro40Dually]

I disconnected the battery for awhile and reconnected. The light is out when I turned it on. We'll see how long it lasts.

[CT-Tundra]

You do NOT have to pull a battery cable to reset a MIL light! With the truck OFF, hold down the trip meter reset button, then move the key to ON (not start) and hold for a few seconds. MIL light will clear.

If your truck is still throwing a code, the MIL light will come back on until you fix the problem.

[spleck]

"Check Engine" and "Maint Req" are two different things. Check engine indicates a code should be available. Reset by disconnecting battery or using a scan tool. Maint Req just means its been 5000 miles or so since the Maint Req light was reset (supposed to be for oil changes, but the timer is manually set). Odo reset button is used when turning the vehicle on to reset.

[TS Support]

This is the Check Engine Light or Malfunction Indicator Lamp (MIL)



This is the Maintenance Required Light or the Engine Oil Replacement Reminder
Light.



Check Engine Light or Malfunction Indicator Lamp (MIL)
OBD II regulations require that the vehicle’s on−board computer
illuminates the Malfunction Indicator Lamp (MIL) on the
instrument panel when the computer detects a malfunction in:
1) The emission control system/components
2) The powertrain control components (which affect vehicle
emissions)
3) The computer

In addition, the applicable Diagnostic Trouble Codes (DTCs)
prescribed by SAE J2012 are recorded in the ECM memory.
If the malfunction does not reoccur in 3 consecutive trips, the
MIL turns off automatically but the DTCs remain recorded in the
ECM memory.

The diagnosis system operates in ”normal mode” during normal
vehicle use. In normal mode, ”2−trip detection logic” is used to
ensure accurate detection of malfunctions. ”Check mode” is
also available to technicians as an option. In check mode,
”1−trip detection logic” is used for simulating malfunction symptoms
and increasing the system’s ability to detect malfunctions,
including intermittent malfunctions.

When a malfunction is first detected, the malfunction is temporarily
stored in the ECM memory (1st trip). If the ignition switch
is turned OFF and then ON again, and the same malfunction is
detected again, the MIL will illuminate.

A DTC can be cleared using a hand−held tester or by disconnecting the neg side of the battery. However if the problem that triggered the illumination of the MIL is detected at startup the light will be illuminated again.

Maintenance Required Light or the Engine Oil Replacement Reminder
Light

Refer to Section 1-6 of your owner's manual.

This light acts as a reminder when to
replace the engine oil.
This light will come on when the ignition
key is turned to “ON” and will go off after
about a few seconds.
When you drive for about 7200 km (4500
miles) after the engine oil replacement,
this light illuminates for about 3 seconds
and then flashes for about 12 seconds
with the ignition key turned to the “ON”
position. If you continue driving without
replacing the engine oil, and if the distance
driven exceeds 8000 km (5000
miles), the light will come on after the
ignition key is turned to “ON” position.
The light will remain on thereafter.
If the light is flashing, we recommend that
you replace the engine oil at an early
opportunity depending on the driving and
road conditions. If the light comes on,
replace it as soon as possible.
The system must be reset after the engine
oil replacement. Reset the system by
the following procedure:
1. Turn the ignition key to the “ACC” or
“LOCK” position with the odometer
reading shown. (For details, see
“Odometer and two trip meters” in this
Section.)
2. Turn the ignition key to the “ON” position
while holding down the trip meter
reset knob.
Hold down the knob for at least 5 seconds.
The odometer indicates “000000”
and the light goes off.
If the system fails to reset, the light will
continue flashing.

[Pro40Dually]

Originally Posted by Pro40Dually

I disconnected the battery for awhile and reconnected. The light is out when I turned it on. We'll see how long it lasts.

I'm thinking (and hoping) that maybe I didn't get the gas cap on snug? I've driven the truck for over a 100 miles and the light (CHECK ENGINE) hasn't came on. We'll see when I fill her up and then drive it awhile.

[lucky02]

Buy a code reader or go to Autozone and get a free check. I had numerous check engine lights at 50K and it was the oxygen sensors on the exhaust manifolds. No trouble since, now have 133k.

[Boosted27606]

Use a SCANGAUGE ( or find a buddy who has one) and check the codes with it and reset.