B0900 code meaning
Wiper Motor Front Circuit
What B0900 means
Open J2012 material, factory manuals and NHTSA bulletins contain no entry for B0900, so it is unconfirmed. The title concerns the windshield wiper motor circuit. GM-era Saab models diagnose it at the relays: the 9-3 sets B3874 06 or B3875 06 when the low- or high-speed relay output stays below 6 V, so the wipers stop, run constantly or only at high speed. GM's 2011 Saab 9-5 logs B3715 and B3875 for the relay control lines and B371A when the park-switch signal does not match the switch position. FMVSS 104 asks for two or more speeds: a fast one with 45 or more wipes a minute and a slower one with 20 or more, separated by 15 or more. Bosch supplies brushless and reversing wiper drives; TI names position control with stall detection as a design requirement. Rear: B0910.
B0900 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modeNot expected
- Repair difficultyMedium, DIY possible
- Typical labor0.3 to 2.5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of B0900
- Wipers do not run, run continuously or only at one speed
- Wipers stop outside the park position
- Poor visibility in rain; do not drive in wet weather until repaired
Common causes of B0900
- Most likelyWiper relay sticking or with burnt contacts
- PossibleWiper motor worn or park switch faulty
- PossibleSeized linkage overloading the motor
- Less likelyDamaged wiring in the scuttle area
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Front wiper motorWiper relayBody control module
What each part of B0900 means
| B | Body system: airbags, seat belts, power seats, lights and climate control. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 00 | The exact fault in that area. |
What to do next
- Note B0900 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about B0900
What does B0900 mean?
B0900 means "Wiper Motor Front Circuit". Open J2012 material, factory manuals and NHTSA bulletins contain no entry for B0900, so it is unconfirmed. It is a generic code, so it means the same on every make.
Is it safe to drive with B0900?
B0900 does not normally turn on the check engine light by itself. Watch for the symptoms above and have it checked soon.
Will B0900 fail an emissions test?
B0900 is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is B0900 to fix?
Difficulty: medium. A typical repair takes 0.3 to 2.5 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will B0900 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.