What Does P1150 Mean?
This code indicates the oxygen sensor fuel trim correction for Engine Bank B (Bank 2), upstream of the catalytic converter, has reached its maximum adjustment limit. The ECM can no longer compensate for the air/fuel ratio deviation detected on Bank 2. This mirrors P1130 but for the opposite engine bank, indicating a significant and persistent lean or rich condition that has exceeded the ECM's adaptive fuel trim authority on Bank 2.
Common Causes
30%
Vacuum leak on Bank 2 intake manifold, gaskets, or associated hoses
25%
Faulty or contaminated upstream O2 sensor on Bank 2 providing incorrect readings
20%
Fuel delivery issue affecting Bank 2 (clogged injectors, fuel distribution imbalance)
15%
Exhaust leak before the Bank 2 upstream O2 sensor
10%
MAF sensor inaccuracy affecting the fuel calculation for both banks
Diagnostic Steps
1
Review short-term and long-term fuel trim values for Bank 2 to determine if the condition is lean (positive trim) or rich (negative trim).
2
Compare Bank 1 and Bank 2 fuel trims; if only Bank 2 is affected, the issue is isolated to that side of the engine.
3
Perform a smoke test on the Bank 2 intake manifold area, vacuum lines, and gaskets.
4
Inspect the Bank 2 upstream O2 sensor waveform for proper switching characteristics.
5
Check for exhaust leaks between the Bank 2 exhaust manifold and the upstream O2 sensor.
6
Test fuel pressure and verify even fuel distribution to all Bank 2 cylinders.
Estimated Repair Cost
$100 - $500
Parts + labor, varies by vehicle and location
This code indicates the oxygen sensor fuel trim correction for Engine Bank B (Bank 2), upstream of the catalytic converter, has reached its maximum adjustment limit. The ECM can no longer compensate for the air/fuel ratio deviation detected on Bank 2. This mirrors P1130 but for the opposite engine b...
The most common cause of P1150 (Oxygen Sensor Fuel Trim at Limit, Engine Bank B, Upstream of Catalytic Converter) is: Vacuum leak on Bank 2 intake manifold, gaskets, or associated hoses
Typical repair costs for P1150 range from $100 to $500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Prolonged operation with fuel trim at its limit can cause catalytic converter overheating (lean) or catalyst saturation (rich). Both conditions increase emissions and can lead to catalyst failure over time.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1150 to identify the root cause.
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