P2180

Code

Generic P — Powertrain

System Too Rich Off Idle Bank 2

Brand: Generic

Type: P — Powertrain

Views: UK: 26 EN: 36 RU: 45

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Page language: EN

Causes

Leaking or stuck-open fuel injector(s) on Bank 2
High fuel rail/line pressure or failed fuel pressure regulator
Contaminated or over-reading MAF sensor (reports less air than actual)
Faulty oxygen (O2) sensor or wideband sensor on Bank 2 (biased high)
Faulty MAP sensor or intake air measurement error affecting fuel calculation
Shorted or incorrectly driven fuel injector (electrical fault)

Symptoms

Check Engine Light (MIL) illuminated, code P2180 set
Engine runs rich off-idle — strong fuel smell or black smoke from exhaust under load
Poor fuel economy
Rough running or hesitation when accelerating off-idle
Possible oil contamination with fuel (dilution) in severe cases

What to check

Read freeze frame and live data with a capable scanner; note engine RPM, load, MAF, MAP, STFT/LTFT for Bank 2, O2 sensor voltages or lambda values
Compare long-term and short-term fuel trims for Bank 1 vs Bank 2 (large negative trims on Bank 2 indicate rich condition)
Inspect wiring and connectors for Bank 2 injectors and O2 sensor for damage, corrosion, or short circuits
Measure fuel rail pressure at idle and off-idle; compare to manufacturer spec
Perform a visual inspection for leaking injectors (fuel smell, wetness) and for intake restrictions
Test MAF sensor output (voltage, frequency, or g/s) against expected values for RPM/load

Signal parameters

Long-term fuel trim (LTFT) Bank 2: large negative (e.g., -10% or lower) when off-idle
Short-term fuel trim (STFT) Bank 2: negative corrections during off-idle
O2 sensor (Bank 2) voltage: high (>0.7–0.9V) or wideband lambda showing
MAF: airflow (g/s) higher or lower than expected for RPM/load (compare to spec or Bank 1)
Fuel rail pressure: above spec or pressure spikes during off-idle
Injector duty cycle or pulse width: higher than expected at given RPM/load

Diagnostic algorithm

Retrieve freeze frame and readiness data. Confirm code is current and note engine conditions when set (RPM, load, temp).
With a scanner, monitor live PIDs at idle and off-idle: LTFT/STFT Bank 2, O2 sensor voltages or lambda, MAF g/s, MAP, fuel rail pressure, and injector duty. Look for negative trims and O2 voltages indicating rich.
Compare Bank 1 vs Bank 2 fuel trims. If only Bank 2 is affected, focus on components specific to that bank (injectors, O2 sensor, wiring).
Inspect wiring/connectors for Bank 2 injectors and O2 sensor. Repair any damaged wiring or poor grounds/connectors.
Perform a fuel pressure test (static and dynamic). Repair fuel pressure regulator, pump, or relief if pressure is above spec.
Check injectors on Bank 2: perform a balance/flow test or use a noid light/oscilloscope to check injector pulse and look for leaking/dripping injectors. Replace or service any faulty injectors.
Clean or test the MAF sensor. Compare MAF output to expected values. Replace if out of specification or inconsistent at off-idle.
Test or swap the Bank 2 O2/wideband sensor if its signal is biased rich or not switching properly. Recheck trims after replacement.
Verify EVAP purge valve operation (should be closed at certain conditions). Replace if it is introducing excessive fuel vapor during off-idle.
If no hardware faults found, check for ECM software updates or reflash as recommended by manufacturer. If suspect, perform further module-level diagnostics.
Clear codes and perform a road test to confirm the fault does not return and trims normalize under the same conditions.

Likely causes

Bank 2 leaking injector(s) or injector(s) stuck open/dripping
High than specified fuel pressure (regulator or return issue)
MAF sensor contamination or incorrect MAF signal at off-idle
Bank 2 O2 sensor biased high or slow to respond
Faulty injector driver circuit (short to ground or stuck on)

Fault status

⚠️ Status

ECM detected air/fuel ratio too rich on Bank 2 during off-idle conditions. Check fuel trims, O2 sensor, injectors, fuel pressure, and intake/airflow sensors on Bank 2.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1-3 hours