Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means that the car's computer is having trouble adjusting the fuel mixture for the engine. It's like when you try to mix the right amount of chocolate syrup in milk to make chocolate milk, but you can't get it just right.
The engine control module (ECM) is unable to properly adjust the air-fuel mixture because it is not receiving correct feedback from the oxygen sensor in Bank 1.
P1148 refers to the ECM's inability to enter closed loop mode for fuel control in Bank 1. The closed loop mode is when the ECM uses the oxygen sensor's feedback to adjust the fuel mixture for optimal combustion. This code indicates that the oxygen sensor may not be providing the necessary feedback or there is an issue with the ECM's ability to interpret the data.
• Check Engine Light on
• Poor fuel economy
• Rough idling
• Faulty oxygen sensor
• Wiring issues or poor connections
• ECM software issue
ECM: Engine Control Module
Oxygen Sensor: A device that measures the oxygen level in the exhaust gases
• Use an OBD-II scanner to confirm the code
• Inspect the oxygen sensor and its wiring
• Check for ECM updates or reflash
• Replace the oxygen sensor
• Repair or replace damaged wiring
• Update or reflash the ECM
• OBD-II scanner
• Multimeter
• Wrench set
$150 - $400
Moderate
• Nissan Altima
• Nissan Sentra
• Infiniti G35
• Regular maintenance of sensors
• Check and fix wiring issues promptly
• Keep ECM software updated
Sensor Issue
• Avoid driving long distances until fixed
• Monitor fuel consumption
• Seek professional diagnosis
Check vehicle warranty for coverage on emission-related components.
P1148 has been commonly reported in Nissan and Infiniti vehicles, often related to oxygen sensor failures.
Moderate – Addressing this issue promptly can prevent further engine performance problems.
Ignoring this code can lead to increased emissions and potential damage to the catalytic converter.
• Engine at operating temperature
• Vehicle in closed loop mode
The oxygen sensor for Bank 1 is located on the exhaust manifold of the engine.
Q: Can I drive with a P1148 code?
A: It's not recommended to drive for long periods with this code, as it may lead to further engine issues.
Q: How do I know if my oxygen sensor is bad?
A: Symptoms include poor fuel economy, rough idling, and the Check Engine Light being on.
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Universal · Digital multimeter
A solid entry-level multimeter for voltage, continuity, resistance, and basic electrical troubleshooting.
Helpful for checking voltage drops, grounds, and basic circuit health when modules are not communicating.
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Universal · Wire connectors and repair kit
Useful when diagnosis points toward damaged wiring, corroded terminals, or connector repairs.
Useful if diagnosis points toward damaged connectors, wiring, or terminal repairs.
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Fitment Required · Vehicle-fitment part
Relevant when the code or supporting diagnostics point toward upstream or downstream oxygen-sensor faults.
This code family often involves upstream or downstream oxygen-sensor diagnosis.
Verify exact sensor position and vehicle fitment before buying.
View options on AmazonThese parts may be related to this fault category, but a code by itself does not confirm exact fitment or guarantee that replacing a part will solve the problem.