Easy ECU Reset Procedures

dholly · Dec 31, 2003

ECU Resetting Procedures

This link was provided earlier for a Basic ECU Reset, but in case it's ever broken I thought a hard copy on site might be appropriate. Perhaps even a spot on the FAQ board?

http://www.technosquareinc.com/350reset.htm

NOTE: Please read all instructions and be familiar with them before any attempts. Timing is extremely critical. If it is NOT DONE within the specified time, the ECU will not reset and the Check Engine Light (CEL) will continue to remain ON. There is NO margin of error. A stop watch or an analog clock with a second’s hand is mandatory.

Basic ECU Reset

Operations Procedures:

1. Confirm that accelerator pedal is fully released, turn ignition switch “ON” (NOT start) and wait 3 seconds.
2. Repeat the following steps (2a and 2b) procedures quickly five times within 5 seconds.
2a. Fully depress the accelerator pedal (HARD).
2b. Fully release the accelerator pedal.
3. Wait 7 seconds, fully depress the accelerator pedal and keep it for approx. 10 seconds until the CEL starts blinking.
4. Fully release the accelerator pedal (while the CEL is still blinking)
5. Wait about 10 seconds.
6. Fully depress the accelerator pedal and keep it for more than 10 seconds.
7. Fully release the accelerator pedal (The CEL light will continue to blink).
8. Turn ignition switch to “OFF” position and now you can start the car. The CEL light should be gone. If the CEL light continues to remain ON, repeat the above steps. Remember, timing is EXTREMELY critical to resetting the ECU. You may even need someone's help to do this correctly.

Note: The following reset procedures are directly from the 2004 G35 Sedan Service Manual.

Accelerator Pedal Released Position Learning

Description:
Accelerator Pedal Released Position Learning is an operation to learn the fully released position of the accelerator pedal by monitoring the accelerator pedal position sensor output signal. It must be performed each time harness connector of accelerator pedal position sensor or ECM is disconnected.

Operation Procedure:
1. Make sure that accelerator pedal is fully released.
2. Turn ignition switch ON and wait at least 2 seconds.
3. Turn ignition switch OFF and wait at least 10 seconds.
4. Turn ignition switch ON and wait at least 2 seconds.
5. Turn ignition switch OFF and wait at least 10 seconds.

Throttle Valve Closed Position Learning

Description:
Throttle Valve Closed Position Learning is an operation to learn the fully closed position of the throttle valve by monitoring the throttle position sensor output signal. It must be performed each time harness connector of electric throttle control actuator or ECM is disconnected.

Operation Procedure:
1. Make sure that accelerator pedal is fully released.
2. Turn ignition switch ON.
3. Turn ignition switch OFF and wait at least 10 seconds.
Make sure that throttle valve moves during above 10 seconds by confirming the operating sound.

Idle Air Volume Learning

Description:
Idle Air Volume Learning is an operation to learn the idle air volume that keeps each engine within the specific range. It must be performed each time electric throttle control actuator or ECM is replaced, or if idle speed or ignition timing is out of specification.

Preparation:
Before performing Idle Air Volume Learning, make sure that all of the following conditions are satisfied. Learning will be cancelled if any of the following conditions are missed for even a moment.

- Battery voltage: More than 12.9V (At idle)
- Engine coolant temperature: 70 - 100 Degrees C (158 – 212 Degrees F)
- PNP switch: ON (Park/Neutral Position Safety Switch - AT only, MT fully depress clutch)
- Electric load switch: OFF (Air conditioner, rear window defogger, headlamps. Note: on vehicles equipped with daytime light systems, if the parking brake is applied before the engine is started, the headlamps will not be illuminated.)
- Steering wheel: Neutral (Straight-ahead position)
- Vehicle speed: Stopped
- Transmission: Warmed-up (For A/T models, drive vehicle for 10 minutes.)

Operation Procedure:
1. Perform "Accelerator Pedal Released Position Learning"
2. Perform "Throttle Valve Closed Position Learning"
3. Start engine and warm it up to normal operating temperature.
4. Check that all items listed under the topic PREPARATION (previously mentioned) are in good order.
5. Turn ignition switch OFF and wait at least 10 seconds.
6. Confirm that accelerator pedal is fully released, turn ignition switch ON and wait 3 seconds.
7. Repeat the following procedure quickly five times within 5 seconds:
7a. Fully depress the accelerator pedal.
7b. Fully release the accelerator pedal.
8. Wait 7 seconds, fully depress the accelerator pedal and keep it for approx. 20 seconds until the MIL stops blinking and turned ON.
9. Fully release the accelerator pedal within 3 seconds after the MIL turned ON.
10. Start engine and let it idle.
11. Wait 20 seconds.
12. Rev up the engine two or three times and make sure that idle speed and ignition timing are within the specifications:

Idle speed A/T: 650rpm, + or - 50 rpm (in P or N position)
Idle speed M/T: 650rpm, + or - 50 rpm (in N position)
Ignition timing A/T: 15 Degrees BTDC, + or – 5 Degrees BTDC (in P or N position)
Ignition timing M/T: 15 Degrees BTDC, + or – 5 Degrees BTDC (in N position)

13. If idle speed and ignition timing are not within the specification, Idle Air Volume Learning will not be carried out successfully. If idle speed and ignition timing are within the specification and Idle Air Volume Learning cannot be performed successfully, find the cause of the incident by referring to the following Diagnostic Procedure:

1. Check that throttle valve is fully closed.
2. Check PCV valve operation.
3. Check that downstream of throttle valve is free from air leakage.
4. When the above three items check out OK, engine component parts and their installation condition are questionable.
5. If any of the following conditions occur after the engine has started, eliminate the cause of the incident and perform Idle Air Volume Learning all over again:

- Engine stalls.
- Erroneous idle.

lead_foot · Jan 5, 2004

dholly · Jan 6, 2004

I think many people don't know there are specific reset procedures that go above and beyond the "Basic ECU Reset" procedure on the Technosquare site. IMO, it is very important to do each after intake/exhaust mods such as the Stillen catback exhaust replacement.

When reading thru the Basic Service Procedures portion of the 2004 Sedan Service Manual, EC 30-44, I found that I had not performed the Idle Air Volume Learning procedure properly after installing my Stillen catback dual exhaust. Why? The info I found posted in other forums was NOT accurate. NONE mentioned Operations Procedure Step 4. in my post above. Specifically, you must check that all items listed under the topic PREPARATION (previously mentioned) are in good order FIRST.

Again, this is directly from the service manual. When I did my first reset, I know for a fact I had Econ A/C ON, and the car had been sitting long enough that coolant was probably below the 70 degree F minimum temp as well. So I blew it and, even though I went through the motions, I didn't actually reset the Idle Air Volume Learning function. When I did it properly, it made a noticable difference.

BTW, I did see the .pdf diagram link and it was helpful. It is important to note that the diagram you posted is for the "Basic ECU Reset". For those interested, there is also a similar diagram in Section EC-44 of the 2004 Sedan Service Manual that visually depicts "Idle Air Volume Learning" as well.

2004 | 6MTs | Diamond Graphite/Graphite
Upstate NY

drazil · Feb 1, 2004

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by dholly

I think many people don't know there are specific reset procedures that go above and beyond the "Basic ECU Reset" procedure on the Technosquare site. IMO, it is very important to do each after intake/exhaust mods such as the Stillen catback exhaust replacement.

When reading thru the Basic Service Procedures portion of the 2004 Sedan Service Manual, EC 30-44, I found that I had not performed the Idle Air Volume Learning procedure properly after installing my Stillen catback dual exhaust. Why? The info I found posted in other forums was NOT accurate. NONE mentioned Operations Procedure Step 4. in my post above. Specifically, you must check that all items listed under the topic PREPARATION (previously mentioned) are in good order FIRST.

Again, this is directly from the service manual. When I did my first reset, I know for a fact I had Econ A/C ON, and the car had been sitting long enough that coolant was probably below the 70 degree F minimum temp as well. So I blew it and, even though I went through the motions, I didn't actually reset the Idle Air Volume Learning function. When I did it properly, it made a noticable difference.

BTW, I did see the .pdf diagram link and it was helpful. It is important to note that the diagram you posted is for the "Basic ECU Reset". For those interested, there is also a similar diagram in Section EC-44 of the 2004 Sedan Service Manual that visually depicts "Idle Air Volume Learning" as well.

2004 | 6MTs | Diamond Graphite/Graphite
Upstate NY
Dholly,
Do you think the ecu adjustments are the same for the 2003 sedan. I put a Borla true duel and an Injen c/a intake but did'nt do anything to my ecu. What should I do to get all the possible gains out of my upgrades?

<hr height="1" noshade id="quote"></blockquote id="quote">

dholly · Feb 1, 2004

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Do you think the ecu adjustments are the same for the 2003 sedan. I put a Borla true duel and an Injen c/a intake but did'nt do anything to my ecu. What should I do to get all the possible gains out of my upgrades?<hr height="1" noshade id="quote"></blockquote id="quote">Should work for all 2003, 2003.5, 2004 G35 coupe or sedan, 350z models. Remember, you don't HAVE to reset your ECU. It should learn and eventually adapt for your intake and exhaust mods. However, if you are short on patience, do each of the resets above according to the instructions. It will shorten the learning process.

2004 | 6MTs | Diamond Graphite/Graphite
Upstate NY

mp5jeff · Feb 4, 2004

thats alot of stuff to just reset the ECU, on my mazda all you do is disconnect the negative terminal on the battery and pump the brakes a few times and whalaa!.

struan87 · Feb 4, 2004

That'll work too, but I think you'll also lose other settings (eg audio).

You know what I drive. Pictures.

thehin · Apr 5, 2004

Ok ive beeen gettin 250 a tank for the last 2 tanks without flooring it or takin it past 4rpms once, i want at least 350. You think resetting the ECU will help?

5AT Black on Black + Performance & Wheel package + 35% legal factory tints

ironrice · Jun 16, 2004

doubt it. Man how are u getting 250 a tank? Are u in stop and go traffic all the time? Do you usually drive city or highway? I get about 340 average and I floor it time to time and also drive in the city, well actually a town cuz I'm stuck here in sh!thole Mississippi(not by choice)

msl558 · May 29, 2009

Idle speed A/T: 650rpm, + or - 50 rpm (in P or N position)
Idle speed M/T: 650rpm, + or - 50 rpm (in N position)
Ignition timing A/T: 15 Degrees BTDC, + or – 5 Degrees BTDC (in P or N position)
Ignition timing M/T: 15 Degrees BTDC, + or – 5 Degrees BTDC (in N position)

13. If idle speed and ignition timing are not within the specification, Idle Air Volume Learning will not be carried out successfully. If idle speed and ignition timing are within the specification and Idle Air Volume Learning cannot be performed successfully, find the cause of the incident by referring to the following Diagnostic Procedure:

1. Check that throttle valve is fully closed.
2. Check PCV valve operation.
3. Check that downstream of throttle valve is free from air leakage.
4. When the above three items check out OK, engine component parts and their installation condition are questionable.
5. If any of the following conditions occur after the engine has started, eliminate the cause of the incident and perform Idle Air Volume Learning all over again:

- Engine stalls.
- Erroneous idle.[/QUOTE]

Can somebody explain this??? I'm clueless about the ignition numbers. how and where can i checked the ignition timing?

Easy ECU Reset Procedures

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