Some states require periodic vehicle emission inspections that include an OBD (On Board Diagnostics) system check. The OBD system continuously monitors functions associated with the emission control system and can identify certain conditions that may affect emissions performance.
If the malfunction indicator lamp comes on
Illumination of the malfunction indicator lamp can mean that the OBD system has detected a problem somewhere within the emission control system. If this occurs, the vehicle may not satisfy the requirements of an I/M test and may need diagnosis or repair before testing. Contact your Toyota dealer to have the Toyota Tacoma inspected and serviced as necessary.
Your vehicle may not pass the I/M test in the following situations:
- If the battery has been disconnected or has become discharged, readiness codes established during normal driving may be erased.
After power is restored, the OBD system needs appropriate driving operation to set these readiness codes again. Depending on driving habits and operating conditions, all required readiness codes may not be completed immediately.
- If the fuel tank cap is loose or has not been properly secured.
A loose fuel tank cap can cause the malfunction indicator lamp to illuminate because the OBD system may interpret the condition as a temporary malfunction. While the lamp is on, the vehicle may not pass the applicable I/M inspection.
When the malfunction indicator lamp still remains on after several driving trips
An error code stored by the OBD system is not necessarily cleared after only a few trips. The vehicle must be driven 40 or more times before the stored error code can be cleared under the specified conditions.
If your vehicle does not pass the I/M test
If the vehicle fails an emission inspection or OBD-related I/M test, contact your Toyota dealer. The dealer can inspect the relevant systems and prepare the vehicle for re-testing after the necessary diagnosis or service has been completed.
