P1151 Lincoln Possible Causes
- Upstream oxygen sensor failure, Bank 2
- Fuel pressure too high or too low
- Dirty/faulty mass air flow sensor
- Engine vacuum leak
- Fuel injector or fuel pressure regulator leakage
- Powertrain control module malfunction
How to Fix Lincoln P1151 Trouble Code?
First check the above “Possible Causes”. Visually inspect related wiring harnesses and connectors for damaged components and check for broken, bent, pushed out, or corroded connector pins.
Technical Explanation
This trouble code indicates that the powertrain control module has detected a system mixture that is too lean, meaning insufficient fuel or excessive air in the system. It is recommended to prioritize checking for vacuum leaks.
Trouble Code Triggering Conditions
When the heated oxygen sensor detects a lean mixture condition at the end of the test, the system attempts to correct the lean condition. This trouble code is set when the fuel control system does not detect signal switching within the calibrated time.
Possible Symptoms
- Check engine light illuminated
P1151 Lincoln Meaning Analysis
Heated oxygen sensor monitoring is a monitoring strategy designed in the onboard diagnostic system to detect HO2S sensor failures or performance degradation that may affect emissions. Under specific conditions, the system checks the output voltage and response rate of the upstream HO2S sensor for fuel control. Simultaneously monitors the output voltage of the downstream HO2S sensor for catalyst monitoring. Initiating HO2S monitoring requires parameters such as engine coolant temperature, intake air temperature, air flow, throttle position, and crankshaft position. Fuel system monitoring and misfire monitoring must be successfully completed before HO2S monitoring can be initiated.
• The HO2S sensor detects oxygen content in exhaust gases, outputting a 0-1.0 volt signal. Under stoichiometric air-fuel ratio conditions, the HO2S generates 0-0.45 volts; under rich mixture conditions, the output voltage is 0.45-1.0 volts
• HO2S monitoring evaluates both upstream and downstream sensor operation status
• After monitoring initiation, the system checks the upstream HO2S signal voltage amplitude and response frequency, comparing against threshold voltages to determine if standards are exceeded
• Executes fixed frequency closed-loop fuel control program, observes upstream HO2S voltage amplitude and output response frequency, evaluates sensor switching capability and response rate through signal sampling
• Determines heating circuit faults by cycling the heating circuit on/off while monitoring corresponding changes, combined with measuring heating circuit current values
• The malfunction indicator light will illuminate after detecting the fault in two consecutive OBD II drive cycles
