What is the meaning of code 51? - 1998 Dodge Caravan

If your airbag code is blinking, and you get 51, it means that your internal thermal fuse in your airbag computer is blown which is caused by an intermittant short to ground on one of the wires in the circuit. When the short to the ground is removed, code 51 flashes with the use of the airbag warning lamp, 5 flashes, pause, 1 flash, longer pause. According to the Ford, this is a nonrepairable fix, you must buy a new air bag module which is a blue box located in the vicinity of the the steering column.

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Type: 1989 Olds Cutlass OBD1 Code 51

Code 34 is for the MAP sensor voltage being low which means the sensor is unplugged or faulty. Code 51 is for a problem with the memory chip inside the computer.
If the engine computer is failing it could set the code 34 even if nothing is wrong with the MAP sensor.
The computer and MAP sensor would need to be checked out.

12 just means the system was reset recently 55 mean end of codes so don't worry about them 2 however code 51 is an oxygen sensor error (O2 Sensor) a bad or shorted O2 sensor can cause it to run very bad and get poor gas mileage.

Code 12; Means the PCM sensed the battery was disconnected and after 50 key cycles, this code will disappear. Code 17; Means the engine is cold too long after start up. Engine coolant temp remains below normal operating range during vehicle travel. The thermostat is stuck open; replace the thermostat. Code 51; The O2 sensor stays below center voltage outout. And indicates a rich fuel condition. This is caused by the stuck open thermostat.

Code 51 means you have to retrieve the real code from the computer.

Ignition switch should be on with engine off.

Locate the black RABS II diagnostic connector.

Disconnect the two halves.
Attach a jumper wire to the black with orange stripe wire side of the diagnostic connector. Ground the jumper wire ground for a few seconds. ABS lamp should start flashing.


Count the flashes. For example, three short flashes followed by one long flash indicates diagnostic trouble Code 4. The code will continue to repeat itself until the key is turned off. A code of 16 means normal system operation.

The last step of the system test always includes clearing the Keep Alive Memory (KAM).

To do this, simply turn off the ignition while the diagnostic connector halves are separated

Then diagnostic connector should be re-assembled.

After getting the real code, then we can look it up and see what the 51 was trying to tell us to look for.

Hi, the code 51 flashing means that the internal fuse is blown and the short to ground is no longer present. If the short to ground returns, the code will change to 13 (air back circuit shorted to ground) or 14 (primary crash sensor circuit shorted to ground), but it will only flash 13 or 14 when the short is present. If the code remains 51, then first find and repair short before replacing the diagnostic monitor (what people call air bag module).
Take care

Hi Branda1, It will have to go to a dealer to repair. Air bags are not something you want to do yourself, very dangerous. Here is what code 51 means.. hope this answers your question.. Cobra

Diagnostic Trouble Code 51—Air Bag Diagnostic Monitor Internal Thermal Fuse—Fuse Blown Due to Intermittent Short to Ground Normal Operation
NOTE: The air bag diagnostic monitor contains an internal thermal fuse that is not serviceable. The thermal fuse is controlled by the microprocessor inside the air bag diagnostic monitor . The microprocessor inside the air bag diagnostic monitor will blow the thermal fuse whenever a short on the deployment circuits occurs. The thermal fuse does not blow because of excessive current flowing through it. DO NOT attempt to short circuit the thermal fuse with a circuit breaker or any other type of fuse.

51= O2 sensor lean,
55= end of codes list

Common fault on FORD

Usually due to a poor connection in the YELLOW PLASTIC CONNECTOR underneath the passenger seat.

Just push it together properly and it should clear the AirBag fault