Replacing a motorcycle battery should be a simple task, akin to adding air to your tires. However, resetting the Throttle Position Sensor (TPS) on a 1998 BMW K1200RS after a battery change can introduce unexpected complications, potentially leading to OBD2 fault codes if not done correctly. While seasoned BMW motorcycle mechanics might find this process straightforward, for those less experienced, especially when relying on manuals like the Clymer BMW K1200RS, GT & LT 1998-2005, the instructions can be misleading and result in engine trouble and potential diagnostic trouble codes.
According to the Clymer manual, on page 267, the procedure to reset the Motronic control unit after battery disconnection involves a seemingly simple step:
“f. Do not start the engine. Turn the ignition switch on and then fully open the throttle once or twice to allow the Motronic control unit to register the throttle-valve positions.”
Many BMW K1200RS owners, including myself initially, have followed these instructions meticulously only to encounter persistent engine stalling issues. The bike may start and idle reasonably well, but upon increasing RPMs and then releasing the throttle to return to idle, the engine frustratingly stalls and dies. This cycle repeats, leaving you stranded and potentially wondering if you’ve triggered any OBD2 fault codes due to the incorrect reset procedure. This is where the Clymer manual’s guidance falls short, assuming a level of prior knowledge that many DIY mechanics simply don’t possess.
The missing piece of the puzzle, unmentioned in the Clymer manual, but crucial for a successful TPS reset on the 1998 BMW K1200RS, involves utilizing the kill switch and a specific sequence of throttle and ignition key manipulations. Digging into online forums, specifically k-bikes.com, reveals a more effective method:
“BTW- Since you disconnected the battery, don’t forget to re-set your fuel delivery. Kill switch on, key on, (DO NOT START THE BIKE) roll the throttle full open three times then turn the key off. You’re now re-set.”
The key differences here are the inclusion of the kill switch and the instruction to turn the key off after the throttle procedure. These seemingly minor omissions in the Clymer manual can lead to significant frustration and potential misdiagnosis, perhaps even prompting unnecessary OBD2 fault code scans when the issue is simply an improperly reset TPS.
The lesson learned is clear: while repair manuals are valuable resources, they can sometimes assume a certain level of expertise and omit crucial steps. For a successful Throttle Position Sensor reset on your 1998 BMW K1200RS after a battery replacement, bypassing potential OBD2 fault code issues related to incorrect TPS data, follow this corrected procedure:
- Turn the ignition key to the “On” position.
- Ensure the kill switch is also in the “On” or “Run” position.
- Crucially, DO NOT START THE ENGINE.
- Fully open the throttle by twisting it all the way. Hold it in the fully open position for 2 to 3 seconds.
- Release the throttle, allowing it to return to the closed position.
- Repeat steps 4 and 5 a total of three times.
- Finally, turn the ignition key to the “Off” position.
By following these steps, incorporating the vital kill switch and key off instructions missing from the Clymer manual, you should successfully reset your 1998 BMW K1200RS Throttle Position Sensor after a battery change. This will help prevent engine stalling issues and avoid triggering unnecessary OBD2 fault codes related to throttle position, ensuring your ride is smooth and trouble-free.
