What this code means
P219C can indicate that cylinder 1's fuel coefficient is outside the specified range.
P219C concerns the air-fuel ratio variation associated with cylinder 1. The procedure also identifies corresponding codes and HDS study-value parameters for the other listed cylinders. Choosing the parameter associated with the stored code keeps the diagnostic subject aligned throughout the checks.
The possible fault areas cover mechanical engine condition, manifold condition and the injector. The diagnosis therefore follows several different kinds of inspection before using the component-specific findings. A numerical study value, a visual manifold finding and the injector-exchange comparison have different roles in that process.
What the vehicle may do
- The PCM may flag an out-of-range cylinder fuel coefficient.
Possible fault areas
- Possible fault areas include engine compression and valve clearance.
- Carbon build-up or oil leakage may involve either manifold.
- The injector may also be a fault area.
Start by addressing the listed related codes or systems. Then follow the compression, valve-clearance, manifold and injector work items in their stated order. The fault-reproduction check uses the HDS parameter matched to the stored cylinder code.
The later manifold and injector checks have their own setup and result interpretation. Keep those individual findings connected to the cylinder-specific confirmation rather than combining all of the listed possible causes into a single conclusion.
Diagnostic path
Understand the stored condition
Related cylinder codes:
- P219C: No. 1 Cylinder Air-Fuel Ratio Variation
- P219D: No. 2 Cylinder Air-Fuel Ratio Variation
- P219E: No. 3 Cylinder Air-Fuel Ratio Variation
- P219F: No. 4 Cylinder Air-Fuel Ratio Variation
Choose the HDS parameter that matches the stored DTC.
- P219C: HDS [Fuel factor study value of No1 cylinder]
- P219D: HDS [Fuel factor study value of No2 cylinder]
- P219E: HDS [Fuel factor study value of No3 cylinder]
- P219F: HDS [Fuel factor study value of No4 cylinder]
On this 2025 Honda Accord 1.5, P219C means No. 1 Cylinder Air-Fuel Ratio Variation. This can mean cylinder 1's fuel coefficient is outside the specified range.
Related-code prerequisite
Troubleshoot any DTCs listed or indicated systems below first.
- A/F Sensor (Sensor 1) [PGM-FI]: P0130, P0133, P2195, P2237, P2238, P2243, P2245, P2251, P2252, P2A00
- A/F Sensor (Sensor 1) Heater [PGM-FI]: P0134, P0135
- No. 1－No. 4 Cylinder Injector(s) [PGM-FI]: P0201, P0202, P0203, P0204
- No. 1－No. 4 Cylinder Misfire [PGM-FI]: P0300, P0301, P0302, P0303, P0304
- No. 1－No. 4 Cylinder Ignition Coil(s) [PGM-FI]: P030A, P030D, P031A, P031D
Engine compression
Before you use compression or valve-clearance results, obtain and follow the correct Engine Compression Inspection and Valve Clearance Adjustment procedures. Use the Engine Compression Inspection to check engine compression.
Valve clearance
Use the Valve Clearance Adjustment procedure to adjust the valve clearance.
Manifold check
Use the Intake Manifold and Exhaust Manifold Visual Inspection to check both manifolds.
Injector check
Use the Injector Inspection to check the injector.
Check whether the fault repeats
Start the engine. With no load and the transmission in P or N, hold the engine at 3,000 rpm until the radiator fan comes on. Then let the engine idle. Drive at a steady engine speed between 1,000 and 1,200 rpm. Then accelerate to 3,000 rpm over about 10 to 15 seconds. Repeat this 3 times or more if needed. In HDS, use PGM-FI > Data List. The listed signals include ECT Sensor 1, Engine Speed, and the cylinder fuel factor study values.
Choose the fuel factor parameter that matches the stored DTC. For P219C, select Fuel factor study value of No1 cylinder. For P219D, select Fuel factor study value of No2 cylinder. For P219E, select Fuel factor study value of No3 cylinder. For P219F, select Fuel factor study value of No4 cylinder. If the selected value is outside the range of 0.82 to 1.21, the failure is duplicated.
The selected study-value parameter determines which cylinder-related information is being observed for the stored code. Use the parameter mapping given at the start of the guide. Read its criterion with the engine condition described in this step, retaining the precise comparison stated by the procedure.
Look for manifold carbon build-up
Before this visual check, the intake manifold and turbocharger must be removed. Look for carbon build-up in the intake manifold and exhaust manifold. There should be no carbon build-up. If the inspection is abnormal, there is a problem with the intake manifold or exhaust manifold involving oil leakage.
This inspection concerns the stated manifold condition. Keep the visual finding attached to the manifold being checked and the preparation given for that inspection. It supplies a different type of result from the cylinder study value and the injector comparison.
Check the injector
Exchange the injector from cylinder 1 with an injector from another cylinder. Start the engine. With no load and the transmission in P or N, hold the engine at 3,000 rpm until the radiator fan comes on. Then let the engine idle. Turn the A/C off, and turn all electrical loads off. In HDS, use PGM-FI > Function Test > CYLINDER AF TEST. Run CYLINDER AF TEST three times under those conditions. The injector failure cylinder should not change.
If this inspection is abnormal, there is a problem with the injector.
This inspection exchanges the injector from cylinder 1 with an injector from another cylinder. The engine and load conditions are then set as stated, and CYLINDER AF TEST is run three times. The result being compared is which cylinder is identified by the injector-failure indication after that exchange.
The recorded criterion is that the injector failure cylinder should not change. An abnormal inspection result points to the injector. This is an exchange between cylinders followed by the stated cylinder-result comparison. Keeping the exchange and the cylinder-result criterion together explains the purpose of this step.
Final check
The checks can cover cylinder fuel-factor variation, compression, valve clearance, manifold condition, and the injector.
The final assessment should retain the stored cylinder code, the matching HDS parameter and the results of the mechanical, manifold and injector checks. Those pieces explain how the diagnosis moves from a cylinder air-fuel-ratio variation to the particular fault-area conclusion supplied by the procedure.
