Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Diagnostic Method
< Timer diagnosis >
Start the count up operation of counters in ECM and in soaking timer IC when the engine is started.
Judge as timer malfunction if the difference between the counter in ECM and counter in soaking timer IC exceeds the allowable limit when the ignition switch is OFF.
Judge as NG when the following conditions are established.
| Malfunction Criteria | Threshold Value |
|---|---|
| osoaktimcpu - osoaktimic/osoaktimcpu | > 0.24 |
| osoaktimcpu = Counter in ECM | |
| osoaktimic = Counter in soaking timer IC |
< Full count diagnosis >
Reset the counter in soaking timer IC and start the count up operation.
Judge as full count diagnosis malfunction if counter in soaking timer IC is not $3FF (1023 count) after 4 seconds.
Judge as NG when the following conditions are established.
| Malfunction Criteria | Threshold Value |
|---|---|
| osoakfcntic | $3FF (1023 count) |
| osoakfcntic = Counter in soaking timer IC |
< Soaking timer IC setting diagnosis >
When setting the activation setting time to soaking timer IC, compare the writing value to soaking timer IC with read out value. Judge as malfunction if the values do not match 3 times in a row.
Judge as NG when the following conditions are established.
| Malfunction Criteria | Threshold Value |
|---|---|
| Writing value and read out value when setting the soaking timer | Unmatch |
< Timer diagnosis (during soaking) >
Wake-up at the predetermined interval until 5 or 7 or 9.5 hours have passed after the ignition switch is OFF, and compare the counter in soaking timer IC with the counter in ECM.
Judge as malfunction if the counter in soaking timer IC is counted up to maximum value (1023 count) when the counter in ECM is 1636 ms, or if the counter in soaking timer IC is not counted up to maximum value (1023 count) when the counter in ECM is 2456 ms.
Judge as NG when the following conditions are established.
| Malfunction Criteria | Threshold Value |
|---|---|
| When any one of the followings is established: | |
|
|
| Counter in ECM | ≤ 1636 ms |
| Counter in soaking timer IC = $3FF (1023 count) | |
|
|
| Counter in ECM | ≥ 2456 ms |
| Counter in soaking timer IC | $3FF (1023 count) |
< Wake-up diagnosis >
Store the number of wake-up activation when the ECM wakes up by the soaking timer IC.
Next time when the ignition switch is ON, if the number of wake-up activation does not reach the predetermined value even though the counter in soaking timer IC operates 1 hour or more, judge as wake-up malfunction. Judge as NG when the following conditions are established.
| Malfunction Criteria | Threshold Value |
|---|---|
| Number of wake-up | Wake-up indication count |
Judge as NG when the following conditions are established.
| Malfunction Criteria | Threshold Value |
|---|---|
| Ignition switch | ON |
| Driving cycle | Completed |
| When any one of the followings is established: | |
|
NG |
|
NG |
|
NG |
|
NG |
|
NG |
Time Needed for Diagnosis: Approx. 5 - 9.5 hours
Malfunction Indicator Light Illumination: Illuminates when malfunction occurs in 2 continuous driving cycles.
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.