P1168
Closed Loop Control Function Bank 2
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The P1168 code is a Nissan/Infiniti-specific code indicating the ECM cannot achieve closed-loop fuel control on Bank 2 — the bank of cylinders that does not contain cylinder #1. This typically appears on V6 and V8 Nissan engines. Closed-loop operation means the ECM actively reads the upstream air/fuel ratio sensor and adjusts fuel injection in real time. When this process fails on Bank 2, the ECM reverts to a fixed open-loop fuel map.
Drivers commonly notice decreased fuel economy, rough idling, and hesitation during acceleration. If P1168 appears alongside P1148, both banks are affected, which points more strongly to a systemic issue like an ECM problem or a major exhaust leak. If only P1168 is present, the issue is isolated to the Bank 2 sensor or its wiring.
Start diagnosis by inspecting the Bank 2 upstream A/F sensor's wiring harness and connector for visible damage. On most Nissan V6 engines, Bank 2 is the front bank near the radiator, making it relatively accessible. If the wiring looks good, replacing the sensor itself is the most common fix. Parts cost $80–$200 for a quality sensor, and professional repair including labor runs $200–$500.
Severity
Symptoms
- •Check engine light is on
- •Rough or unsteady idle
- •Decreased fuel economy
- •Engine hesitation under acceleration
- •Possible surging at highway speeds
- •Stronger exhaust odor
Likely Causes
The upstream A/F ratio sensor on Bank 2 has failed or degraded, preventing the ECM from entering closed-loop fuel control on that bank.
Burnt, corroded, shorted, or disconnected wiring in the Bank 2 upstream sensor harness disrupts the signal needed for closed-loop operation.
The internal heater element in the A/F sensor has failed, preventing the sensor from reaching operating temperature quickly enough for closed-loop control.
An exhaust manifold crack or gasket leak near the Bank 2 sensor allows ambient air to contaminate the exhaust reading.
Estimated Cost
Professional Repair
Includes parts + labor
Common Fixes
- Replace the upstream air/fuel ratio sensor on Bank 2
- Repair or replace damaged wiring and connectors to the A/F sensor
- Repair exhaust leaks near the Bank 2 sensor location
- Clear codes and verify closed-loop operation returns