LumpyVR4
Supporting Member
- 91
- 49
- May 21, 2014
-
Sydney,
Australia
I had an ABS error code and it took a little digging to find out how to get the code without a reader, so I thought I'd make a how to for ECU and ABS error codes.
Both the ECU and ABS put out error codes as a series of pulses that you can read with an analog display multi-meter, or a LED connected to the diagnostic port.
To use a multi-meter you simply select a DC range suitable to read 12v and hold its probes on the correct pins of the diagnostic port.
An easier way is to wire up and LED that will flash the codes at you. You need a standard LED and a 470 ohm resistor wired in series, and a couple of mini female spade connectors to go on the diagnostic ports pins. You can get all of this from any electronics store.
To read ECU aka CEL error codes, with the engine off connect your meter or LED to pin 1 and 12 (ground). For ABS codes connect to pin 4 and 12.
Turn on the ignition, without starting the car.The ECU will send out pulses corresponding to numbers. If there is a series of constant short pulses (about 1 per second) there are no error codes.
The ECU uses short pulses for 0-9 and long pulses for 10s. For example an error code of 22 would be two long pulses (a few seconds each) followed by two short ones. Multiple codes are outputted one after the other and then repeated. To clear the codes disconnect the battery for more than 10 seconds. Below is a table of the ECU error codes.
To get ABS codes, start the car. If the initial ABS check fails, leave the car running and read the codes. If it fails the check it does once you are moving, again leave the car running once the light comes on and check the codes. Below are the ABS codes.
Both the ECU and ABS put out error codes as a series of pulses that you can read with an analog display multi-meter, or a LED connected to the diagnostic port.
To use a multi-meter you simply select a DC range suitable to read 12v and hold its probes on the correct pins of the diagnostic port.
An easier way is to wire up and LED that will flash the codes at you. You need a standard LED and a 470 ohm resistor wired in series, and a couple of mini female spade connectors to go on the diagnostic ports pins. You can get all of this from any electronics store.
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To read ECU aka CEL error codes, with the engine off connect your meter or LED to pin 1 and 12 (ground). For ABS codes connect to pin 4 and 12.
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Turn on the ignition, without starting the car.The ECU will send out pulses corresponding to numbers. If there is a series of constant short pulses (about 1 per second) there are no error codes.
The ECU uses short pulses for 0-9 and long pulses for 10s. For example an error code of 22 would be two long pulses (a few seconds each) followed by two short ones. Multiple codes are outputted one after the other and then repeated. To clear the codes disconnect the battery for more than 10 seconds. Below is a table of the ECU error codes.
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To get ABS codes, start the car. If the initial ABS check fails, leave the car running and read the codes. If it fails the check it does once you are moving, again leave the car running once the light comes on and check the codes. Below are the ABS codes.
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