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Home >> Toyota >> 1994 >> Celica L4-132 2164cc 2.2L DOHC (5S-FE) >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> Manufacturer Code Charts >> Engine Control System >> DTC 26 >> Inspection Procedure

Inspection Procedure


DTC 26 Air-Fuel Ratio Rich Malfunction

INSPECTION PROCEDURE
1. Check voltage between terminals VF1 and E1 of data link connector 1 (DLC1).
- Warm up engine to normal operating temperature



- Using Special Service Tool (SST) (09843-18020), connect terminals TE1 and E1 of data link connector (DLC1).
- Connect positive probe to terminal VF1 and negative prove to terminal E1 of data link connector 1.
- Warm up the oxygen sensor by running engine at 2,500 rpm for about 2 minutes.
- Then, maintaining engine at 2,500 rpm, count how many times needle of voltmeter fluctuates between 0 and 5 volts.

RESULTS
- OK - 8 or more fluctuations in 10 seconds.
- Type 1 failure - 0 volts, steady.
- Type 2 failure - 5 volts, steady.

- Type 1 failure proceed to step 2.
- Type 2 failure proceed to step 7.

2. Check voltage between terminals OX1 and E1 of the data link connector (DLC1).
- Warm up engine to normal operating temperature
- Measure voltage between terminals OX1 and E1 of DLC1 when engine is suddenly raced to full throttle.

OK - The voltage should be 0.5 V or higher at least once.

HINT: Perform inspection within 1 second.

- If OK proceed to step 7.
- If not OK proceed to step 3.

3. Check for open and short in harness and connector between engine control module and main oxygen sensor, engine control module and DLC1.
- If OK proceed to step 4.
- If not OK repair or replace harness or connector.

4. Check each item found to be a possible cause of problem.
- Check each circuit found to be a possible cause of trouble according to the results of the check in steps 1 or 2. The numbers in the table below show the order in which the checks should be performed.
1 Faulty sensor installation.
2 Air leakage
3 Misfire
4 Fuel system
5 Injector circuit
6 Characteristics deviation in engine coolant temperature sensor.
7 Characteristics deviation in intake air temperature sensor.
8 Characteristics deviation in manifold absolute pressure sensor.
9 Valve timing.

- If OK proceed to step 5.
- If not OK Repair or replace.

5. Check compression.
- If OK proceed to step 6.
- If not OK repair engine as necessary.

6. Does malfunction disappear when a good main[1] oxygen sensor is installed?
- If Yes, Replace main [1] oxygen sensor.
- If No, check and replace ECM.

7. Check each item found to be a possible cause of problem.
- Check each circuit found to be a possible cause of trouble according to the results of the check in step 1. The numbers in the table below show the order in which the checks should be performed.

Oxygen Sensor Diagnostic Chart:




- If OK proceed to step 8.
- If not OK repair or replace items as necessary.

8. Check compression.
- If OK proceed to step 9.
- If not OK repair engine as necessary.

9. Does malfunction disappear when a good main [1] oxygen sensor is installed?
- If Yes, replace main [1] oxygen sensor.
- If No, check and replace engine control module.

[1] "Main" oxygen sensor reference is for Ca. spec. vehicles only. All others have only 1 oxygen sensor.

NOTICE: A set driving pattern is necessary for detection this trouble code. Be sure to follow that pattern when performing a test drive to confirm repair. For a description of the prescribed driving pattern, refer to DTC 21: Description.
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