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· Registered
39 Posts
Discussion Starter · #1 ·
hey all. tonight i was cruizin with some friends to the movies and i was just playin around and got it up to 90 or so and let off and started to slow down. now when i let the motor slow it down itself and not hit the brakes hard or anything after a few secs the CEL came on and i was like ? so i put it neutral turned it off and turned it back on. it went away? now i was wondering if since i havent replaced my VSS and it is being all funny with the d4 light blinking; would that cause the ecu to throw a light cause it doesnt like me doing that? just hope its not something else worse.

any help is appreciated.


· Registered
1,046 Posts
have the codes checked on the ECU, that will tell you your problem. Your VSS may be the problem, but its always best to have it all checked out. Stealers only rip you off on diagnostic checks. Get a code checker on ebay, theyre about 30-40 bucks or more depending on which one you get. After you get the code, check the book that came with it and then do some more research on it on the internet. Youre better off buying the part on your own, shop around first. Then have a credible mechanic replace and install the parts and clear the codes off of the ECU. If the CEL doesnt come on within the next 4 days of normal driving youre good to go.

· EDM Honda Legend Coupe
4,675 Posts
What It Means
The function of the CEL (Check Engine Lamp) on the dashboard is checked by the ECU on every time during ignition is turned ON. The lamp should illuminate for 2 sec's and then extinguish. In normal operation, the lamp should not come on while driving.

Probably Cause
When the CEL remains ON it and when you turn your car off, a code has been stored. The CEL will not come on until the code gets deleted. That means: If the CEL lamp lights while the vehicle is operating, the ECU has sensed a system fault. The fault may be either loss of signal or signal out-of-range, either high or low. Additionally, when the Check Engine lamp is lit, the ECU has entered the default or fail-safe mode in which fixed values are substituted for the faulty or missing signal.

What It Does
If, during diagnosis, the service connector is jumpered, the Check Engine lamp will light, even if no faults are present. When repairs or diagnosis are completed, the memory should be checked for any stored codes and cleared if necessary. Recording and clearing the codes before a diagnostic test drive can be helpful in separating intermittent faults from current or hard faults. Please see "Resetting ECU". That is your way to get it fixed.

Resetting ECU
Sometimes it may be useful to reset the ECU memory. Although that maybe done by removing the battery for around 20 minutes or so, this will also kill your clock and radio presets.
A more elegant way is:
On '91-'95 Legends remove the ACG fuse (No. 15 Fuse 7.5A) in the interior fuse panel for 20 sec's. Note that this will also clear the seat memory !

ECU Jumper Wire Connector
It's for your car's self-diagnosis system. This is a plug that is jumpered to get the codes to diagnose problems that trigger your check engine and D4 lights. That female connector on the other end should just be a "dead" connector that doesn't have any wires coming out of it. It's just to hold the service check connector in place. What you do is take a paper clip, uncurl it and stick each end into the connector. Turn the ignition to the ON position and count the blinks of the Check Engine and/or D4 light. These blinks are codes that are then cross-referenced in the manual to indicate trouble spots.

ECU Jumper Wire Location

How The Jumper Wire Works
If your CEL has illuminated, it's more helpful to know WHY it has lit up instead of just guessing at the problem. How do you find out what the error is? Well you will need a short peice of wire or a paperclip. On the passenger side of your car, under the dash beneath the glove box, you will find a cover above the kickpanel that houses a blue connector that has two wires. What you need to do is turn the ignition off, and using the piece of wire or paperclip, jump the blue connector so that you connect the two wires together. Basically stick one end of the paperclip or peice of wire into one prong on the connector and stick the other end of the paperclip or wire into the other prong. Once you have done this, turn the key to the IGN position and watch your CEL light. It will illuminate in a series of flashes.

Extracting ECU Codes
With the car either running or the key in the ON position, perform the necessary steps above and observe the blinking of the light. The light will blink displaying all the codes in sequence and then repeating them. You will notice that there will be LONG flashes and SHORT flashes. All of the ECU trouble codes are two-digits. LONG flashes determine the TENS digit by the number of times it flashes, and SHORT flashes determine the ONES digit by the number of times it flashes. So now you have the codes, what good are the numbers? What do they mean?

ECU Codes And Its Meaning
Our ECU codes from 1 to 9 are indicated by a series of short flashes: Two digit codes use a number of long flashes for the first digit followed by the number of short flashes for the second digit. So a code 43 will be represented by 4 long and 3 short flashes. The position of codes in a sequence can be helpful in doing diagnostics. A display showing "1-1-1-pause-9-9-9" indicates two problems occurring at different times. A sequence showing "1-9-1-9-1-9" indicates two problems occurring at the same time.


3 LONG flashes followed by 4 short flashes, then a long pause. If that is the only code the ECU is throwing, then the code will simply repeat until you remove the key. If, however there are more than one ECU error code, then you will see a different series of flashes followed by the long pause. Once all the ECU codes have been displayed, they will continuously cycle until you remove the key.


ECU Codes Description
Code # Explanation
1 => Oxygen Sensor, Left
2 => Oxygen Sensor, Right
3 => Manifold Absolute Pressure Sensor (MAP)
4 => Crank Angle Sensor No 1
5 => Manifold Absolute Pressure Sensor (MAP)
6 => Coolant Temperature Sensor (TW)
7 => Throttle Angle Sensor (TAS)
9 => Cylinder No 1 Position (1st Sensor)
10 => Intake Temperature Sensor (TA)
11 => Idle Mixture Adjustment Sensor (IMA) (w/o CATA)
12 => EGR Sensor
13 => Atmospheric Pressure Sensor (PA)
14 => Electronic Idle Control Module (ICM)
15 => Ignition Output Signal
16 => Fuel Injector
17 => Vehicle Speed Sensor (VSS)
18 => Ignition Timing Adjustment
23 => Knock Sensor, Left
41 => Oxygen Sensor Heater, Left
42 => Oxygen Sensor Heater, Right
43 => Fuel Supply System, Left
44 => Fuel Supply System, Right
45 => Fuel Metering, Left
46 => Fuel Metering, Right
53 => Knock Sensor, Right
54 => Crank Angle Sensor No 2
59 => Cylinder No 2 Position (2nd Sensor)

Once you have determined the codes, you can simply remove the paperclip or wire from the connector and replace it back. Good luck, Bryan ;) -Mike
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