Question: What If A Car Computer Cant Be Read?

What causes ECU no communication?

With error message showing “No-Communication”! In most cases, communication issues can be caused by various reasons including: ignition-key position, connector-voltage issues, incorrect communication protocol, hung ECM, missing or bad data, and OEM-updated ECM software that is unknown to the scan tool.

What to do if there is no communication between the vehicle and the scanner?

TEST 1: Connect the positive DMM lead to DLC pin 4 and the negative DMM lead to the negative battery terminal, using jumper wires if necessary. Do not connect to the body or chassis ground but to the battery terminal directly.

How do you diagnose a car computer problem?

Scan tools connect to your car’s On-Board Diagnostic II (OBD-II) system, letting you peer under your car’s hood without even opening it. They easily plug into your car’s OBD-II port — usually located under the steering wheel — and allow you to read information from its computer system.

CAN OBD scanner damage car?

Apart from some “killer commands”, the ECU might have been destroyed electrically. The OBDII-Interface can implement several different data buses with different voltage levels. If the bus lines get connected to +12V, this could destroy something.

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Can a ECU be repaired?

ECU repairs can be very expensive. The part alone can cost between $1,000 and $3,000, depending on the make and model of your vehicle. Fortunately, an ECU can be repaired or reprogrammed in many cases —thus preventing the need to actually replace an ECU.

Why is my scanner not connected?

Check the cable between the scanner and your computer is firmly plugged in at both ends. If you’re connecting the scanner to a USB hub, connect it to a port attached directly to the motherboard instead. Unplug any other devices, particularly scanning devices, that may be causing a conflict with the scanner.

Can you use a code reader on a car that won’t start?

Sure. But to pull data you’ll have to at least key the vehicle ON. If you’re getting fuel (at the right pressure) and spark, then you either have a compression/timing belt issue, (if you have the 4 cylinder) or your injectors are not opening.

Will AutoZone do a free diagnostic?

AutoZone does. If your light is on, and you are wondering why, head down to your local AutoZone where one of our store associates can help diagnose the issue through our free Fix Finder service.

Is it safe to leave OBD plugged in?

From their web site FAQ: You can leave the Bluetooth models plugged in if you are driving the vehicle frequently. Depending on the battery condition, if you leave your car sitting for days to weeks, we recommend that you remove the OBD2 device. According some other users, it does draw power when the car is off.

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Can I start my car with OBD2?

3 Answers. Ultimately the answer is yes you can. To qualify this answer, though, you can only control some things, but not all things, then only on some vehicles. You can do simple things through the port, such as turn the A/C pump on, or any other thing which is controlled by the computer (PCM).

How do you tell if OBD codes have been cleared?

If the vehicle does not support the above datapoints you can use the smog check feature to check for indications of codes being recently cleared. When codes are cleared all vehicle emissions tests are reset and will display a status of ‘not complete’.