K1200RS ABS reset

If you fit a sidecar to a K1200, and you fit leading links you will have to disconnect the front ABS sensor and its connection at some point. After you finished, with everything re-connected, it is highly likely you will suffer the dreaded ABS error of alternate flashing of the ABS lights when you switch on the ignition, after you start the engine, or after you ride off (normal at around 5mph or more). In fact it is quite common fault to appear during ownership on the K1200 with ABS2, even without a sidecar fitted.

So what happens; Turn the key on, the two lights will flash together and continue to do so until the self test is complete (which doesn’t happen until you ride off), at around 5mph they should extinguish. If the self test fails they will begin to flash alternately. The moment when the fault appears will help you to know what caused it. If it happens before you start the engine, it is an item that is tested at power up. If it happens after you’ve started the engine, it is most likely low battery voltage. If it happens when you ride away, it’s most likely a wheel speed sensor or could be the modulator.

I will try and explain (on a K1200RS 98 model) along with pictures how to clear the memory of faults and return the ABS warning lights to normal on start up. Please note; if you have not resolved the cause of the fault, for example a bad wheel sensor, the warning lights will return to their warning state after the bike has gone through it’s self test process.

But first, I will list the faults and how to read them. Under the seat and attached to the left side of the frame there is a diagnostic connector. It is round in shape and has a removable cap. See pic later

Remove the cap and locate pin 2 it is connected to the brown/blue wire. Simply connect an analogue meter between pin 2 and earth. Turn on the ignition. The meter will at first settle at around 10 volts. Now, watch the needle carefully. The needle will fall to a number of lower voltages in a series of pulses. Count the number of times the needle drops. This number is your fault code. The following codes have appeared on various forums . I cannot guarantee their accuracy..

1. Front pressure modulator.
2. Rear pressure modulator
3. Front wheel speed sensor
4. Rear wheel speed sensor
5. Battery voltage too low
6. ABS relay
7. ABS control unit
8. Sensor gap.

Note; Sometimes ABS2 will fault without showing a fault code.

So here we go; To carry out a reset, this is what I did. You need to get to pin 21 on the ABS controller. The connector is plugged into the ABS unit which can be seen next to the battery holder towards the left hand side under the seat. You do not have to remove the battery to get to this. The easiest and the best way is to remove the rear wheel and the plastic front under tray section.

To remove the plastic section it is simply 2 nuts and 1 Allen screw.

The pin 21 connector on the ABS controller.

To remove, push down on the metal tang arrowed (quite hard as it is sprung steel) and pull on the connector from the bottom. Note; the connector continues to be held in at the top of the unit as it has a plastic tang which hooks under the top of the ABS unit. There is a small screw in the top of the connector. Do not remove this it has nothing to do with its release. See next picture.

Cut the cable tie, roll back the rubber protector where the wires enter the connector. This will reveal two screws. There is another screw at the top of the connector (the one mentioned above not to remove when disconnecting the connector from the ABS unit ). You can now remove all three screws and then pull apart the connector.

You will then be able to locate pin 21 . The inner of the connector has the terminal numbers along its side. Note; Terminal 21 is vacant.

Strip a thin wire and thread it through the hole and then bent a small amount over to hold it in place being careful not to interfere with other terminals.

Screw the connector back together, thread your wire though the rubber cover. You will see on my bike that the rubber sleeving for the wires has perished, basically heat and aging, it is not an uncommon fault on the K1200.

But with it out and easily assessable you can repair it with heat resistant wiring loom tape. Make sure you fit a new cable tie to the rubber cover.

Before you refit the connector I would recommend you use an electrical contact spray on the contacts. One of the most common faults on any K bike is a poor electrical connection or a corroded one.

You can use a straight pin and wire and connect to pin 2 or as here scotch lock a wire to the brown and blue wire on the diagnostic connector and connect it to the negative terminal of the battery.

Turn the ignition key to on and then touch the wire from pin 21 (yellow) to the negative terminal on the battery and hold there for about 8 to 10 seconds, although mine reset immediately. You will get one solid light during this time, then remove / disconnect both wires. After you remove the wires the ABS lights should go from alternate flashing to normal flashing simultaneously, if they don’t simply switch off and then switch on the ignition.

You can take it a step further. Leave all the wires connected in place and then wire in two momentary switches (like a horn button) one in the wire from pin 21 ( my yellow wire) and one in the wire from the brown and blue wire (my black wire) on the diagnostic connector.

Here you will see I have tidied them up at a suitable location under the seat. So now when the ABS needs resetting, all I have to do is lift of the seat, Turn on the ignition, press the black button and hold and then press the yellow button for 8 seconds, let go of both and the ABS is reset.

The above procedure only clears any record of fault from the electronic memory. It cannot and will not repair a physical fault on the bike. If you have a faulty wheel sensor, other ABS component or even a poor battery and you do not fix it, the ABS lights will return to alternate flashing mode following self test, the ABS function is automatically disabled and they flash annoyingly.

Final note; In regards to low battery voltage, you will find that after charging or fitting a new battery the ABS lights when you turn on the ignition, the two lights will most likely flash together and lull you into thinking you have cured the issue. That is until you ride off and they then flash alternately. I found that (in my case) you have to perform a reset to clear any record of a fault from the electronic memory.

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