P1151 Lincoln Possible Causes
- Upstream oxygen sensor fault, Bank 2
- Fuel pressure too high or too low
- Air flow sensor dirty/faulty
- Engine vacuum leak
- Fuel injector or fuel pressure regulator leak
- Powertrain control module fault
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 connector pins for breaks, bends, push-outs, or corrosion.
Technical Explanation
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
- Engine warning light illuminated
P1151 Lincoln Meaning Analysis
Heated oxygen sensor monitoring is an onboard diagnostic system monitoring strategy designed to detect HO2S sensor faults 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 downstream HO2S sensor output voltage 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 begin.
• HO2S sensor detects oxygen content in exhaust, outputting 0-1.0 volt signal. Under stoichiometric air-fuel ratio conditions, HO2S generates 0-0.45 volt; under rich mixture conditions, output voltage is 0.45-1.0 volt
• HO2S monitoring evaluates both upstream and downstream sensor operation status
• After monitoring initiation, system checks upstream HO2S signal voltage amplitude and response frequency, comparing against threshold voltage 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 heating circuit on/off while monitoring corresponding changes, combined with measuring heating circuit current values
• Malfunction indicator light illuminates after fault is detected in two consecutive OBD II drive cycles