P219C on Audi
Cylinder 1 Air/Fuel Ratio Imbalance
P219C on Audi vehicles indicates cylinder 1 air/fuel ratio imbalance. Au7o has documented this code across 3 Audi models — most commonly on A4, Q5, SQ5. Generic SAE J2012 code. The ECM/PCM estimates each cylinder's contribution to the air/fuel mixture using the upstream oxygen/air-fuel sensor signal together with crankshaft and camshaft position data. P219C sets when cylinder 1 is running significantly richer or leaner than the other cylinders on its bank. It indicates an imbalance (combustion is occurring but the ratio is wrong), which is distinct from a misfire code.
Common Causes of P219C
- •Clogged or leaking fuel injector on cylinder 1
- •Intake/vacuum leak near cylinder 1's intake port
- •Fouled spark plug or weak ignition coil on cylinder 1
- •Faulty upstream oxygen / air-fuel ratio sensor
- •Contaminated MAF sensor
- •Low or fluctuating fuel pressure
- •Worn valve seals, rings, or low compression on cylinder 1
P219C on Audi by Model
Audi A4(1 issue)
- 2009-2021 A4 2.0T Gasoline-Quality Deposit Diagnosis - TSB 2014753/132009-2021
Audi states that contaminated gasoline or gasoline with insufficient deposit-control additives can contribute to deposits on intake valves, the intake manifold, fuel injectors and combustion chambers. Possible results include rough running after cold start, extended cranking, hesitation, rough idle, reduced performance, poor fuel economy or an MIL with supported misfire, lean-system or cylinder-imbalance faults. This does not establish a universal A4 2.0T intake-valve defect, mandatory walnut-blasting interval or fixed failure mileage.
Audi Q5(1 issue)
- 2009-2025 Q5 Gasoline-Quality Deposit Diagnosis - TSB 2014753/132009-2025
Audi states that contaminated gasoline or gasoline with insufficient deposit-control additives can contribute to deposits on intake valves, the intake manifold, fuel injectors and combustion chambers. Possible results include rough running after cold start, extended cranking, hesitation, rough idle, reduced performance, poor fuel economy or an MIL with misfire, lean-system or air/fuel-ratio-imbalance faults. This does not establish a universal Q5 intake-valve defect, a mandatory walnut-blasting interval or a fixed failure mileage.
Audi SQ5(1 issue)
- Fuel-Quality or Deposit-Related Rough Running and Misfire Diagnosis2014-2025
Audi states that contaminated gasoline or gasoline with insufficient deposit-control additives can contribute to deposits in injectors, combustion chambers, the intake manifold and intake valves, with rough running, hesitation, reduced performance, poor fuel economy or related ECM faults. This does not establish a universal SQ5 intake-valve defect, a mandatory walnut-blasting interval or a fixed mileage. Audi separately warns that unapproved fuel additives are not permitted on 2018-2025 EA839 V6 TFSI SQ5 models because a negative effect on engine life cannot be ruled out.
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View P219C across all makes →Frequently Asked Questions
What does P219C mean on Audi?▼
P219C stands for "Cylinder 1 Air/Fuel Ratio Imbalance." Generic SAE J2012 code. The ECM/PCM estimates each cylinder's contribution to the air/fuel mixture using the upstream oxygen/air-fuel sensor signal together with crankshaft and camshaft position data. P219C sets when cylinder 1 is running significantly richer or leaner than the other cylinders on its bank. It indicates an imbalance (combustion is occurring but the ratio is wrong), which is distinct from a misfire code. On Audi specifically, this code is documented across 3 models.
What causes P219C on Audi vehicles?▼
Common causes on Audi: Clogged or leaking fuel injector on cylinder 1, Intake/vacuum leak near cylinder 1's intake port, Fouled spark plug or weak ignition coil on cylinder 1, Faulty upstream oxygen / air-fuel ratio sensor, Contaminated MAF sensor. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P219C on a Audi?▼
Repair costs vary widely depending on the root cause and specific Audi model.
Which Audi models have P219C documented?▼
Au7o has documented P219C on 3 Audi models: A4, Q5, SQ5.