Toyota Tacoma manuals

Toyota Corolla Repair Manual: Inspection procedure

Hint

: read freeze frame data using the hand-held tester or the obd ii scan tool. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the airfuel ratio was lean or rich, etc. At the time of the malfunction.

1 Check other dtc output(in addition to dtc p0420)

  1. Connect the handheld tester or the obd ii scan tool to the dlc3.
  2.  turn the ignition switch on and push the handheld tester or the obd ii scan tool main switch on.
  3.  select the item diagnosis / enhanced obd ii / dtc info / current codes.
  4.  read the dtcs.

Result:

Hint:

Hint

: if any other codes besides p0420 are output, perform the troubleshooting for those dtcs first.

2 Check for exhaust gas leakage

2 Check for exhaust gas leakage

3 Inspect heated oxygen sensor(bank 1 sensor 1)

3 Inspect heated oxygen sensor(bank 1 sensor 1)

Refer to the hint below.

4 Inspect heated oxygen sensor(bank 1 sensor 2)

4 Inspect heated oxygen sensor(bank 1 sensor 2)

Refer to the hint below.

Replace threeway catalytic converter(exhaust manifold)

Replace threeway catalytic converter(exhaust manifold)

Hint

: handheld tester only:

  1. Perform active test using handheld tester (a/f control).

Hint

: a/f control is active test which changes the injection volume 12.5 % Or +25 %.

  1.  Connect the handheld tester to the dlc3 on the vehicle.
  2.  Turn the ignition switch on.
  3.  Warm up the engine by running the engine speed at 2,500 rpm for approximately 90 seconds.
  4.  Select the item diagnosis / enhanced obd ii / active test / a/f control.
  5.  Perform a/f control with the engine in an idle condition (press the right or left button).

Result: heated oxygen sensor reacts in accordance with increase and decrease of injection volume
+25 %  rich output: more than 0.5 V, 12.5 %  Lean output: less than 0.4 V

Notice

: there is a delay of few seconds in the sensor 1 (front sensor) output, and there is about 20 seconds delay at maximum in the sensor 2 (rear sensor).

The following of a/f control procedure enables the technician to check and

The following of a/f control procedure enables the technician to check and graph the voltage outputs of both the heated oxygen sensors.

For displaying the graph indication, enter active test / a/f control / user data, then select o2s b1s1 and o2s b1s2 by pressing yes button and push enter button before pressing f4 button.

Circuit description
The ecm compares the two waveforms of the heated oxygen sensors located before and after the catalyst to determine whether or not the catalyst performance has deteriorated. Airfuel ratio feedba ...

Evaporative emission control system
Dtc p0441 evaporative emission control system incorrect purge flow Dtc p0446 evaporative emission control system vent control circuit ...

Other materials:

Calibrating the compass
The direction display deviates from the true direction determined by the earths magnetic field. The amount of deviation varies according to the geographic position of the vehicle. If you cross over a map boundary shown in illustration, the compass will deviate. To obtain higher precision or p ...

Description
When troubleshooting obd ii vehicles, the only difference from the usual troubleshooting procedure is that you need to connect the vehicle to the obd ii scan tool complying with sae j1978 or the handheld tester, and read various data output from the vehicles ecm. Obd ii regulations re ...

Purpose of the readiness tests
The onboard diagnostic (obd ii) system is designed to monitor the performance of emissionrelated components and report any detected abnormalities in the form of diagnostic trouble codes (dtcs). Since the various components need to be monitored during different driving conditions, t ...

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