Performance Olds 307
Understanding The ECM & System
Cold Air Induction
Ignition & Spark
Tuning The Q Jet
Carburetor & Intakes 1
Carburetor & Intakes 2
Intake Manifolds
Great Links
Who's The Man!!!
Contact Me!


ArrowYou will need to check the ECM and system! Don't waste your money on one of the "scanners" from the parts store. A paperclip can accomplish all that the parts store Scanner can do. On a cutlass or regal under the radio by the driver's right knee you'll see a connector with two rows of pins (Check out the picture on the right), on all other 307 Olds powered cars it will be under the steering wheel just above your knee. That is the ALDL (Assembly Line Diagnostic Link) connector. Pin A is in the upper right-hand corner (as you're looking at it), Pin B is right beside it. Bend a paper clip or small piece of wire into a U shape and insert it into both pins A and B so that they are connected together.Turn the ignition switch to the ON position, but don't start the car. You'll see the "Check Engine" (or "Service Engine Soon" on some models) light flash some codes. Error codes are two digits, and the light flashes out the first digit, pauses, and then the second digit. It will repeat each code two more times (total of three) before displaying the next one. The first and last code will always be a code 12 (flash, pause, flash, flash, long pause, repeat). This code is normal and means that no tach signals are making it to the computer (because the engine isn't started). If you don't get a code 12, something is wrong with your jumper or your computer. Make a note of any codes that come up and look them up on the chart below then read under the chart where I explain the best areas to check for each error code. Feel free to Contact Me! if you have any problems, I will try my best to help you! 


Ok I am going to explain what I look for first when I experiance an error code, if you cant figure it out after that then you will need the manual for the full troubleshoot page on that error code, if you do not have the manual you can Contact Me! and I will email you the page to your error code that you have.
 Code 12 - This is normal when you have jumped the  pin A and pin B with a paper clip but the engine is not running.
 Code 13 - Most likely means the oxygen sensor is disconnected or an open in the wire going to the oxygen sensor.
 Code 14 - Most likely the wire going to the coolant sensor is shorted to a ground or the engine got way to hot or the sensor is just bad.
 Code 15 - Most likely the coolent sensor is unpluged or the wire is has an open
 Code 21 - The TPS is unpluged for misadjusted, could also be just a bad TPS.
 Code 22 - Most likely just means the TPS is adjusted to low or the idle has recently been set lower without making a TPS adjustment as well.
 Code 23 - Most likely the M/C solenoid is just unpluged at the carburator or a open in the wires going to the M/C solenoid.
 Code 24 - ? Never had one of them?
 Code 32 - Most likely the Boro sensor is just disconnected or needs replaced
 Code 34 - Most likely the vacume sensor is just disconnected or you have put on the wrong vacume sensor.
 Code 41 -  No matter what the name of the error code implies it is usaly the fault of the vacume sensor or you have replaced a vacume sensor for a MAP sensor, they both look the same so be careful!
 Code 42 - ? Never had one of them?
 Code 43 - ? Never had one of them?
 Code 44 - Most likely a bad oxygen sensor or you are just running really really lean for a long period of time
 Code 45 - Most likely a bad oxygen sensor or you are just running really really rich for a long period of time
 Code 51 - You have a bad prom or installed the wrong prom for your ECM
 Code 54 - Most likely a bad M/C solenoid or ECM
Hope that helps



Arrow On the picture above is a chart showing the terminals of the ECM and what the voltage should read with the key on or engine running or circuit open. Checking your ECM with this chart and a digital volt meter will help find problems that where not able to or not bad enough to trip a "service engine soon" light. Do not use an anolog volt meter on your ECM or you could cause damage. 
1. just drop the ECM out of its resting place but keep it hooked up to its terminals. Most ECMs are located behind the carpet panel just to the right of the passingers feet but on your full size deltas and full size buicks it can be located just over the passingers feet behind some plastic.
2. remove the blue caps that are on the back side of the ECM terminals with a flat head so that you can gain access to the rear of the terminals with a digital volt meter
3. connect the ( + ) wire from the digital volt meter into the rear of the ECMs terminal that you want to test. and the ( - ) to any good ground using the 20 VDC selection on the meter.
 Use the chart above to know what your ECM should be reading if the systems working properly. To check some areas of the ECM you will have to drive the car with the volt meter connected to ECM, example is the "high gear switch"- this switch sits in the transmission and tells the ECM when you are in 4th gear but you have to get the car to 4th before you will be able to check this at the ECM terminals, another is the "transmission converter clutch solenoid" to make sure the ECMs sending a apply signal you will have to drive the car but sometimes the car must run for 5 minutes before it starts sending this signal. Its best to test the "coolent engine temp sensor" on a cold engine and then on a warm engine to make sure it is varible. Move tha car slowly to check the VSS, the voltage should raise to 12 then back down almost to 0 then back to around 12 over and over while you drive very slowly. While checking the vacume sensor make sure you tap the gas to change the engines vacume so you can make sure the sensor is still active and not just stuck sending one reading like bad sensors often do. This is the best way to check your TPS while you have the volt meter connected to the TPS terminal, with the engine off but key in run press on the gas peddle slowly while watching the meter, the voltage should be around 0.40 - 0.50 at idle and go over 4.0 volts on full peddle WOT, there should be no dead spots and the sensor shoud read steady if your foot is not moving. If you have any questions feel free to Contact Me!



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