Fault code C0042 belongs to the C group, the chassis side with brakes, steering and systems like iBR. Sea-Doo owners search for it most, but it shows up on other BRP vehicles too. That is exactly why it pays to look at every official meaning.
What BRP says about C0042
The official BRP fault code list (DiagApi 25.13.0) has several entries for C0042:
- Low brake pressure switch (LPS). This entry appears twice, so it comes from more than one module.
- Shifter sensor A is open or shorted to ground.
- Brake lever sensor (BRLS) signal A open or shorted to ground.
Which one applies depends on the vehicle and the module. A vehicle with hydraulic brakes and a pressure switch reports something different than a Sea-Doo with iBR, where a lever is read electronically. The partner code C0043 describes the same thing for signal B, on both the shifter sensor and the brake lever sensor. If C0042 and C0043 are stored together, that leans toward a shared cause like a connector, power supply or harness.
Common causes
- Connector at the sensor or lever: corrosion, moisture, not latched. On a watercraft after salt water, one of the top reasons.
- Wire open or chafed to ground: especially where things move when you steer.
- Failed sensor: after an impact, water intrusion or plain age.
- For the brake pressure version: the switch itself or its wiring. Check the brake system mechanically on the vehicle as well.
- Low battery voltage that makes sensor signals messy.
Check order
- Read the plain text and the module. Whether iBR, ECM or another module reports it decides where you look.
- Check the status. Active or stored. Deal with active codes first.
- Look at the other codes. C0043, voltage codes or communication codes change the picture.
- Battery and grounds. Watch voltage in live data, check the terminals.
- Connector at the sensor. Unplug, clean, dry, reconnect firmly.
- Trace the wiring. Move the bars and look for chafing.
- Clear, test, read again.
Reading and clearing with the app
M-JET DIAGNOSTIC is a dongle for the diagnostic port plus an app for iOS and Android. The app reads the fault memory of the ECM, cluster, iBR and, depending on the vehicle, other modules, and shows every code in plain language with its status. So you see right away which C0042 meaning your vehicle reports. On iBR models the app also shows iBR status and offers iBR auto calibration once the cause is fixed.
More on iBR codes is in reading and resetting Sea-Doo iBR faults and sorting out C0073 and C2161.
Only clear C0042 after you have checked or repaired something. If it comes right back, the cause is still there.
Common mistakes when chasing C0042
- Swapping the sensor on a hunch. Without the plain text and a check of the connector and wiring, that gets expensive and often fixes nothing.
- Only clearing the code. If a corroded connector is the cause, C0042 is back after the next ride.
- Missing the partner code. If C0042 and C0043 are stored together, look first for what both signals share.
- Contact spray instead of drying. If there is water in the connector, dry it out first, then connect it properly.
When to see a shop
Anything brake related gets zero risk. If the brakes do not work the way they should, or the code stays active after you have checked connectors and wiring, take it to a qualified shop. Same if a sensor has to be replaced and the system needs setup afterward.
Frequently asked questions
Does C0042 mean the same thing on a Sea-Doo and a Can-Am?
Not necessarily. The BRP list has several meanings for C0042. The plain text from your vehicle tells you which one applies.
Can I ride with C0042?
If braking or shifting could be affected, sort that out first. Check the code before you head out.
What is the difference between C0042 and C0043?
Per the BRP list, C0042 covers signal A and C0043 signal B of the shifter or brake lever sensor.
