P03A5 on Volkswagen
Cylinder #2 Pressure Variation Too High
P03A5 on Volkswagen vehicles indicates cylinder #2 pressure variation too high. Au7o has documented this code across 1 Volkswagen model — most commonly on Golf R. P03A5 is set when the engine control module detects that the combustion pressure signal for cylinder #2 is too high or varies beyond the expected range, as reported by that cylinder's in-cylinder pressure sensor (typically integrated into the glow plug on diesel engines that use cylinder-pressure-based combustion control). It is part of the P039C–P03BB block of per-cylinder pressure sensor codes found on engines such as GM/Opel/Vauxhall/Saab 2.0L diesels. It indicates the measured peak combustion pressure for cylinder 2 is out of its normal window, pointing to either a sensor/wiring fault or an actual combustion/mechanical abnormality. Typical repair costs on Volkswagen range from $1,500 to $4,200, depending on the specific model and root cause.
Common Causes of P03A5
- •Faulty cylinder #2 pressure sensor (often combined with the glow plug unit)
- •Wiring or connector problems in the sensor 5V reference, signal, or low-reference circuits
- •Abnormal combustion in cylinder 2 (faulty/leaking fuel injector causing over-fueling)
- •Mechanical issue raising cylinder pressure (carbon buildup, valve or head gasket problem)
- •Corroded or poor sensor ground/connection
- •ECM software/calibration or, rarely, ECM internal fault
P03A5 on Volkswagen by Model
Volkswagen Golf R(1 issue)
- EA888 Timing Chain Stretch and Tensioner Failure2014-2019
The 2.0 TSI EA888 Gen 3 (CJXC/DJHA engine codes) in the Mk7/Mk7.5 Golf R is prone to timing chain stretch and timing chain tensioner degradation, typically surfacing around 100,000-140,000 km. The plastic-bodied tensioner loses hydraulic tension and the chain develops slack, allowing the chain to skip teeth. In severe cases the timing jumps (owners report a slip of ~1.5 teeth), throwing a crankshaft/camshaft correlation fault and, if it lets go at speed, causing piston-to-valve contact and major internal damage. This is the same chain-drive architecture covered by an Audi TPI for 2015 cars. Symptoms most often start as a metallic rattle on cold start or a sudden loud rattle while driving.
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View P03A5 across all makes →Frequently Asked Questions
What does P03A5 mean on Volkswagen?▼
P03A5 stands for "Cylinder #2 Pressure Variation Too High." P03A5 is set when the engine control module detects that the combustion pressure signal for cylinder #2 is too high or varies beyond the expected range, as reported by that cylinder's in-cylinder pressure sensor (typically integrated into the glow plug on diesel engines that use cylinder-pressure-based combustion control). It is part of the P039C–P03BB block of per-cylinder pressure sensor codes found on engines such as GM/Opel/Vauxhall/Saab 2.0L diesels. It indicates the measured peak combustion pressure for cylinder 2 is out of its normal window, pointing to either a sensor/wiring fault or an actual combustion/mechanical abnormality. On Volkswagen specifically, this code is documented across 1 model.
What causes P03A5 on Volkswagen vehicles?▼
Common causes on Volkswagen: Faulty cylinder #2 pressure sensor (often combined with the glow plug unit), Wiring or connector problems in the sensor 5V reference, signal, or low-reference circuits, Abnormal combustion in cylinder 2 (faulty/leaking fuel injector causing over-fueling), Mechanical issue raising cylinder pressure (carbon buildup, valve or head gasket problem), Corroded or poor sensor ground/connection. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P03A5 on a Volkswagen?▼
Repair costs on Volkswagen range from $1,500 to $4,200, depending on the specific model and root cause.
Which Volkswagen models have P03A5 documented?▼
Au7o has documented P03A5 on 1 Volkswagen model: Golf R.