When your car’s computer isn’t communicating properly, you can reprogram it with a tool such as Cardone Industry’s flash tool reprogrammer, according to Scotty Kilmer. First, you have to determine that the problem is the computer and not something else.
What does your car’s computer do?
Most new cars have several computers or engine control modules. Older cars from the 1990s and early 2000s might have just the one engine control module. Newer cars might have the engine control module, plus:
- ABS control module
- Control module for the seats, power door locks, windows, mirrors
- Transmission control module
- Automatic climate control computer
The one we are concerned with is the engine control module, which controls the engine’s fuel and ignition systems. You’ll need two scanners for this: the flash reprogrammer and a scan tool to read codes. Continue reading to learn how and when to use both scanners.
Is the Check Engine Light on?
Your computer could malfunction without throwing a check engine light. The computer reads information from some sensors and sends information to others. It also turns the check engine light on when a sensor reading is not within the normal range.
However, if the engine control module is not working properly, it might not turn on the check engine light. Since the engine control unit can’t diagnose itself, you have to figure it out.
Additionally, if you bought a used car, someone could have removed the light bulb for the dummy light, or the bulb could have burned out.
To find out if the light even exists, watch the dash while turning the key to the “On” position. You should see all of the lights on the dash light up. If you don’t see the check engine light, turn the key off, wait a couple of minutes; then repeat the process.
If you don’t see the check engine light, the bulb has burned out or was removed. You can still diagnose your vehicle without it – you just can’t see when you have a problem.
Scan for Codes
Even if your vehicle’s engine light is not on, if you suspect a problem with the engine control unit, you should scan for codes. It rarely happens, but sometimes a sensor is not working, but the engine control unit doesn’t throw a code.
Plug a code scanner into the port located under the driver’s side dashboard. It’s usually right under the steering wheel. Turn the scanner on; then follow the instructions for the brand of scanner you have.
Write down all of the codes. Some scanners tell you what the codes are. Others do not, and you’ll have to look them up on the internet.
Replace the pertinent part; then plug the scanner back in to erase the codes before you try to start the vehicle.
Are the Codes Related?
While you could have more than one problem, that is rare. Since the engine control module can’t diagnose itself – at least not on the older vehicles, you have to play detective. If the codes are related, then the problem is probably with one of those sensors or another function throwing the sensor off.
If you see a PO172 (System too rich) and a PO303 (Cylinder misfire detected), the codes are related, and you know to look for a problem in the ignition system. You’ll probably also have an oxygen sensor code.
However, the problem is probably with the coil or plug, not the oxygen sensor, since you have a misfire. The misfire causes the rich running condition. The oxygen sensor then tells the computer that the vehicle is running rich and makes adjustments to compensate.
Keep in mind that other sensors could cause a misfire situation, but these types of situations are more difficult to diagnose. You really need a tool such as the Snap-On Vantage or other tool that reads the operating ranges of the sensors.
When it can’t compensate, it will send a signal back to the computer to turn the engine light on and store the codes.
When the Codes are not Related
This is where things get sticky. If you have an oxygen sensor code, a MAP sensor code, a coolant temp sensor code and other codes that are most likely not related, you can bet that the engine control module went south.
You can try to reprogram the computer to see if it will start working. If the problem is physical, no amount of reprogramming is going to help it. You can verify your findings by removing the computer cover and smelling it. If it smells like rotten eggs, it’s time for a new one.
The PROM chip in the old computer is usually still good. Be sure to remove the PROM from the old computer and put it in the new computer.
Reprogram the Computer
Some of the newer computers can diagnose themselves. If you get a P0600, PO601, PO602, PO603, PO605, PO606, or PO607 code, you can try to reprogram the computer.
The steps to do this are:
- Download the software updates from your vehicle manufacturer’s website
- Plug the reprogramming tool into the OBDII port under the dash
- Plug the USB cable into your computer
- Click on the correct vehicle make and follow the instructions
The reprogramming takes about a half-hour, according to Scotty Kilmer. When the reprogramming is done, remove the reprogramming scanner; then try to start your vehicle.
Visit Vehicle History
Before you buy a vehicle, especially one you might want to repair, read reviews and customer comments on the make and model. Vehicle reviews and input from customers can help you determine if the repairs are something you want to tackle for that particular model.
To learn more about vehicle care, maintenance, and repairs, and to see professional reviews and customer comments, visit Vehicle History.
