Resetting/Relearning the ECU
Thread Starter
Joined: Dec 2007
Posts: 2,757
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Resetting/Relearning the ECU
I have to emissions test my S, I've cleared all of the codes and replaced the necessary components. I drove 30 miles thinking that it was surely enough since it was over the course of 5 drive cycles (completely cool to warmed up) and it wasn't ready. So I took a couple of extended drives yesterday for an additional 40 miles (totalling 75 miles since reset) and the o2 sensor was still not ready according to the emissions scanner (I saw it for myself).
My driving consisted of:
stop and go in the city
cruising at 30-35
cruising on the highway for 5+ miles at 70 on the speedo (65 IRL because of gears)
10+ starts from cold to 3bars.
Does anyone know the parameters in which the computer is looking for? I found a few threads and follow their instructions to no avail. I'm starting to wonder if my weak starts are related and actually shorting the power out (effectively resetting the ECU every time I start).
Also, does anyone know how to determine if the engine codes are ready or not without a scanner? With the key in the Ignition Position 2 (with the engine OFF), does the check engine light stay lit or does it go out?
My driving consisted of:
stop and go in the city
cruising at 30-35
cruising on the highway for 5+ miles at 70 on the speedo (65 IRL because of gears)
10+ starts from cold to 3bars.
Does anyone know the parameters in which the computer is looking for? I found a few threads and follow their instructions to no avail. I'm starting to wonder if my weak starts are related and actually shorting the power out (effectively resetting the ECU every time I start).
Also, does anyone know how to determine if the engine codes are ready or not without a scanner? With the key in the Ignition Position 2 (with the engine OFF), does the check engine light stay lit or does it go out?
Thread Starter
Joined: Dec 2007
Posts: 2,757
Likes: 22
I'll try that tomorrow when I have some time. There's an additional symptom (the starting problem) that may be relevant but I haven't been able to determine if that's the issue or not.
The car will some times not crank to start. I bypassed the clutch interlock switch completely and the symptom still persists. However, if I leave the ignition in the Ignition II position for 15 seconds before pressing the start button, it fires right up without issue.
The car will some times not crank to start. I bypassed the clutch interlock switch completely and the symptom still persists. However, if I leave the ignition in the Ignition II position for 15 seconds before pressing the start button, it fires right up without issue.
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Joined: Jan 2014
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From: Austin, TX
I've never had to follow this procedure, a day or two of normal driving around has always set readiness. I'd agree with the battery/charging assessment. But here it is from the 02 manual, for what it's worth:
If the testing facility determines that the readiness codes are not set, you will be requested to return at a later
date to complete the test. If you must get the vehicle re-tested within the next two or three days, you can
condition the vehicle for re-testing by doing the following.
Make sure the gas tank is nearly, but not completely, full (around 3/4).
Make sure the vehicle has been parked with the engine off for 8 hours or more.
Make sure the ambient temperature is between 20° and 95°F.
Without touching the accelerator pedal, start the engine and let it idle for 20 seconds. Keep the vehicle on Neutral.
Increase the engine speed to 2,000 rpm and hold it there until the temperature gauge rises to at least 1/4 of the scale (approximately 3 minutes).
Then drive in city/suburban traffic for at least 10 minutes. When traffic conditions allow, let the vehicle coast for several seconds without using the accelerator pedal or the brake pedal. Select a nearby lightly traveled major highway where you can maintain a speed of 50 to 60 mph (80 to 97 km/h) for at least 20 minutes. Drive on the highway in 5
th. Do not use the cruise control. When traffic allows, drive for 90
seconds without moving the accelerator pedal. (Vehicle speed may vary slightly; this is okay.) If you cannot do this for a continuous 90 seconds because of traffic conditions, drive for at least 30 seconds, then repeat it two more times (for a total of 90 seconds).
If the testing facility determines the readiness codes are still not set, see your Honda dealer.
date to complete the test. If you must get the vehicle re-tested within the next two or three days, you can
condition the vehicle for re-testing by doing the following.
Make sure the gas tank is nearly, but not completely, full (around 3/4).
Make sure the vehicle has been parked with the engine off for 8 hours or more.
Make sure the ambient temperature is between 20° and 95°F.
Without touching the accelerator pedal, start the engine and let it idle for 20 seconds. Keep the vehicle on Neutral.
Increase the engine speed to 2,000 rpm and hold it there until the temperature gauge rises to at least 1/4 of the scale (approximately 3 minutes).
Then drive in city/suburban traffic for at least 10 minutes. When traffic conditions allow, let the vehicle coast for several seconds without using the accelerator pedal or the brake pedal. Select a nearby lightly traveled major highway where you can maintain a speed of 50 to 60 mph (80 to 97 km/h) for at least 20 minutes. Drive on the highway in 5
th. Do not use the cruise control. When traffic allows, drive for 90
seconds without moving the accelerator pedal. (Vehicle speed may vary slightly; this is okay.) If you cannot do this for a continuous 90 seconds because of traffic conditions, drive for at least 30 seconds, then repeat it two more times (for a total of 90 seconds).
If the testing facility determines the readiness codes are still not set, see your Honda dealer.
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Thread Starter
Joined: Dec 2007
Posts: 2,757
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Figured out what the issue was for O2 not ready. I had double defoulers. Ran the car for 2 minutes at 55mph on the freeway and it tripped a check-engine-light immediately.
Gonna try to give it a few drive cycles to reset, if it still isn't clear i'll just redo the re-learning procedure. I think the O2 readings were too drastically different from prior logs
Gonna try to give it a few drive cycles to reset, if it still isn't clear i'll just redo the re-learning procedure. I think the O2 readings were too drastically different from prior logs
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