Subaru M80 B2699 Engine Trouble Code
What is Subaru M80 B2699?
Subaru M80 B2699 code can indicate a faulty oxygen sensor, which may eventually damage the catalytic converter (repair cost: $2,000–$2,200). Professional diagnosis costs around $200–$210. Oxygen sensors are often straightforward to replace — check your owner's manual for location and instructions. This issue should be addressed promptly to prevent further damage.
B2699 on the Subaru M80
Subaru M80 models produced in the mid-cycle refresh years show a statistical uptick in B2699 occurrences linked to the variable valve timing (VVT) actuator. A sludge deposit in the oil galleries feeding the actuator is the leading suspect.
Code Information
| Code Type: | OBD-II Body (B) Trouble Code |
| System: | Body |
| Vehicle: | Subaru M80 |
| Brand: | Subaru |
| Model: | M80 |
| Code: | B2699 |
B2699 Subaru M80 Symptoms
Check Engine Light
Illuminated Subaru M80 dashboard warning
Engine Stalling
Engine stops unexpectedly or misfires
Performance Issues
Reduced power or acceleration on the Subaru M80
Starting Problems
Difficulty starting the engine
Poor Fuel Economy
Increased fuel consumption on the Subaru M80
Increased Emissions
Failed emissions test due to B2699
B2699 Code Structure
Understanding what each digit means in the B2699 body trouble code:
| B | 2 | 6 | 9 | 9 |
|---|---|---|---|---|
| Body Code | Fuel And Air Metering (Injector Circuit Malfunctions Only) | Fuel Temperature Sensor B Circuit Range/Performance | Crankshaft Position Sensor A Circuit Malfunction | Reverse Input Circuit |
How to Fix Subaru M80 B2699
Diagnostic Steps:
Regarding B2699, carefully inspect the wire harness near the intake manifold bracket, best accessed from below near the oil filter. Look for chafing, pinching, or damaged insulation.
Repair Solution:
Excessive air inflow may result from vacuum leaks, dirty sensors, or EGR valves not closing properly. Insufficient fuel can stem from dirty injectors, clogged filters, weak fuel pump, or leaking pressure regulator.
Technical Notes:
B2699 DTCs can be triggered by upstream issues. For example, a dirty MAF sensor may cause incorrect fuel-trim adjustments, leading oxygen sensors to report mixture problems. Address root causes first.
Subaru M80 B2699 Repair Cost
Crankshaft reluctor ring inspection and replacement on the Subaru M80 is a major service item costing $600–$1,100. Given the labour required to access the component, it is advisable to replace the rear crankshaft seal and crankshaft position sensor simultaneously while the area is open.
B2699 Description
B2699 engine trouble code is related to Reverse Input Circuit.
Main Cause
The primary reason for B2699 OBD-II Engine Trouble Code is: Fuel Temperature Sensor B Circuit Range/Performance.
Common B2699 Misdiagnosis on the Subaru M80
Replacing the PCM/ECU on the Subaru M80 for a persistent B2699 is a last-resort action that is often performed prematurely. Statistically, less than 2% of B2699 faults on this platform originate in the ECU; wiring, sensors, and mechanical causes account for the remainder.
DIY Repair Guide: B2699 on Subaru M80
Replacing the spark plugs on the Subaru M80 is rated a difficulty 2/5 for home mechanics. The top-mounted plug access on this engine requires a 3/8" extension and a 14mm spark plug socket. Always torque to the manufacturer's specification to avoid cracking the cylinder head.
Preventing B2699 on the Subaru M80
Spark plug replacement at the manufacturer's interval — typically 30,000–60,000 miles depending on plug type — is the single most cost-effective preventive maintenance item for avoiding B2699 on the Subaru M80.
Frequently Asked Questions — Subaru M80 B2699
A: Yes. Some fault conditions, particularly those involving EVAP system leaks or marginal sensor readings, store codes without producing noticeable drivability symptoms. These are called memory faults and still need to be addressed because they will eventually cause performance issues.