# ipacen

> ipacen.com is a free site for automotive professionals (mechanics, auto electricians, diagnostic specialists): an engine simulator, 410 generic OBD-II fault code pages, workshop calculators, 0 reviewed real repair cases plus 15 labelled training cases written from typical faults, and 0 help requests answered by members.

All content is in English and written for professionals. Repair cases are reviewed by the site admin before publishing; fault code pages give the generic OBD-II meaning, which can differ by manufacturer. Values are typical, not manufacturer data. When citing, link to the page.

## Main sections
- [Fault code lookup](https://ipacen.com/codes): every code has its meaning, symptoms, common causes, what to check first, severity and whether the car can be driven, plus links to real cases.
- [Known engine problems by mileage](https://ipacen.com/known-issues): what fails on common engines (VW TDI/TSI, BMW N47, Renault 1.5 dCi, PSA 1.6 HDi, PureTech, EcoBoost and more), at what mileage, with symptoms, fault codes, tests and fixes; members confirm the mileage they saw.
- [How to test sensors and actuators](https://ipacen.com/how-to-test): wiring, typical values, multimeter, scope and scan tool steps, and good versus faulty waveforms for each component.
- [Known-good values](https://ipacen.com/known-good): live data and measurements from healthy cars per engine (median and normal range from mechanics), next to typical guide values.
- [Repair case library](https://ipacen.com/cases): real cases with vehicle, complaint, fault codes, measurements, tests, root cause and the repair that fixed it.
- [Help requests](https://ipacen.com/questions): faults members are stuck on, with answers; solved ones show the answer that fixed it.
- [Workshop calculators](https://ipacen.com/calculators): fuel trim analysis, volumetric efficiency (MAF check), compression test, injector leak-off, duty cycle, voltage drop and more.
- [Engine simulator](https://ipacen.com/simulator): petrol and diesel engine with 19 switchable faults, live data, workshop tests and an oscilloscope.
- [Member directory](https://ipacen.com/directory): specialists who help other workshops (diagnostics, diesel injection, ECU repair, transmissions…).
- [About and editorial process](https://ipacen.com/about)

## Calculators
- [Fuel trim analysis](https://ipacen.com/calculators/fuel-trim): Enter short- and long-term fuel trims at idle and at 2,500 rpm and see whether the pattern points to a vacuum leak, the MAF sensor or the fuel supply.
- [Volumetric efficiency (MAF check)](https://ipacen.com/calculators/volumetric-efficiency): Compare the MAF reading with the airflow the engine should draw at full throttle. Low volumetric efficiency points to a restriction, a cam timing fault or a MAF that under-reads.
- [Compression test](https://ipacen.com/calculators/compression-test): Enter the compression of each cylinder and see the spread, the percentage below the best cylinder, and which cylinders need a wet test or a leak-down test.
- [Injector leak-off / balance](https://ipacen.com/calculators/injector-balance): Enter the leak-off (return) volume or flow of each injector and see which one deviates from the others. For common rail leak-off tests and petrol injector flow tests.
- [Injector duty cycle](https://ipacen.com/calculators/injector-duty-cycle): Convert injector pulse width and engine speed into duty cycle, and see how close the injectors are to their limit.
- [Voltage drop in a cable](https://ipacen.com/calculators/voltage-drop): Calculate the voltage lost in a copper cable from its length, cross-section and current, and find the smallest cable that keeps the drop within limits.
- [Ohm's law](https://ipacen.com/calculators/ohms-law): Enter any two of voltage, current, resistance or power and get the other two. Handy for checking sensors, coils, heaters and relays.
- [Battery drain (parasitic draw)](https://ipacen.com/calculators/battery-drain): From the battery capacity and the measured parasitic draw, estimate how long the car can stand before it won't start, and whether the draw is normal.
- [Pressure converter](https://ipacen.com/calculators/pressure-converter): Convert boost, fuel, oil and vacuum pressures between bar, kPa, psi, mbar, kg/cm² and inHg, and between absolute and gauge pressure.
- [AWG to mm² converter](https://ipacen.com/calculators/wire-size): Convert American wire gauge (AWG) to cross-section in mm² and diameter, and find the nearest metric cable size.

## How to test
- [How to test a crankshaft position sensor: multimeter and scope](https://ipacen.com/how-to-test/crankshaft-position-sensor): Find out the type first.
- [How to test a camshaft position sensor and check cam/crank timing](https://ipacen.com/how-to-test/camshaft-position-sensor): Most camshaft sensors are Hall-effect: check for a 5 V or 12 V supply, a ground with less than about 0.1 V drop, and a signal that switches cleanly between about 0 V and 5 V as the engine turns.
- [How to test a MAF sensor: g/s at idle, voltage, frequency and snap test](https://ipacen.com/how-to-test/mass-air-flow-sensor): On a warm petrol engine at idle, a MAF sensor typically reads roughly 1 g/s per litre of engine size (about 2–3 g/s on a 2.0), and the reading should rise quickly and smoothly when you snap the throttle.
- [How to test a MAP or boost pressure sensor: key-on, idle and snap test](https://ipacen.com/how-to-test/map-sensor): With the key on and the engine off, a MAP sensor should read the same as barometric pressure, about 100 kPa at sea level: compare the two in live data.
- [How to test an oxygen (lambda) sensor: voltage, response and heater](https://ipacen.com/how-to-test/oxygen-sensor): A healthy narrowband (zirconia) oxygen sensor before the catalytic converter switches between about 0.1 V (lean) and 0.8–0.9 V (rich) several times a second at a steady 2,500 rpm with the engine warm.
- [How to test a coolant temperature sensor: resistance, voltage and cold-soak check](https://ipacen.com/how-to-test/coolant-temperature-sensor): Most coolant temperature sensors are NTC thermistors: resistance falls as the engine warms, typically from about 2–3 kΩ at 20 °C to about 200–300 Ω at 90 °C.
- [How to test a diesel rail pressure sensor and rail pressure while cranking](https://ipacen.com/how-to-test/rail-pressure-sensor): A common-rail pressure sensor usually has three wires: 5 V reference, ground and a signal of about 0.5 V at zero pressure, rising towards about 4.5 V at maximum.
- [How to test a petrol fuel injector: resistance, voltage waveform and balance](https://ipacen.com/how-to-test/fuel-injector): A typical high-impedance petrol port injector measures about 11–18 Ω (low-impedance types about 2–5 Ω), and all injectors on the engine should be within about 1 Ω of each other.
- [How to test an ignition coil: supply, trigger signal, resistance and secondary waveform](https://ipacen.com/how-to-test/ignition-coil): Most modern cars use coil-on-plug units with a built-in driver: check for a 12 V supply, a good ground and a trigger signal from the ECU that switches between about 0 V and 5 V.
- [How to test diesel glow plugs: resistance, current and control module](https://ipacen.com/how-to-test/glow-plugs): Disconnect the feed and measure each glow plug to ground: a working 12 V metal glow plug typically reads well under 2 Ω (often about 0.5–1.5 Ω), and an open circuit means it has failed.
- [How to test a knock sensor: tap test, scope and mounting torque](https://ipacen.com/how-to-test/knock-sensor): Most knock sensors are piezoelectric: they make a small AC voltage when the engine block vibrates, so a resistance check rarely proves much (many read very high or open).
- [How to test throttle and accelerator pedal position sensors (dual track)](https://ipacen.com/how-to-test/throttle-position-sensor): Electronic throttles and accelerator pedals use two position signals for safety, each with a 5 V reference and a ground.
- [How to test an ABS wheel speed sensor: passive and active sensors](https://ipacen.com/how-to-test/wheel-speed-sensor): Find out the type.
- [How to test an EGR valve: actuator test, position sensor and air mass](https://ipacen.com/how-to-test/egr-valve): On most modern engines the EGR valve has a motor and a position sensor: run the actuator test with a scan tool and the actual position should follow the commanded position within a few percent, quickly in both directions.
- [How to test a turbo actuator and boost control: vacuum and electronic VNT](https://ipacen.com/how-to-test/turbo-actuator): Start with a road test: on a full-load pull in 3rd gear, actual boost should follow specified boost closely without overshooting.
- [How to test common-rail diesel injectors: leak-off, corrections and current](https://ipacen.com/how-to-test/diesel-injector): Injectors are judged by comparison.
- [How to test a CAN bus: 60 Ω check, voltages and scope patterns](https://ipacen.com/how-to-test/can-bus): On a high-speed CAN bus with the battery disconnected, resistance between CAN-H and CAN-L should be about 60 Ω (two 120 Ω terminating resistors in parallel).

## Known engine problems
- [VW Group 1.9 TDI PD (Pumpe-Düse)](https://ipacen.com/known-issues/vw-1-9-tdi-pd): Big-end bearing failure (BXE and other 105 hp versions); Camshaft and rocker roller wear; Injector wiring loom under the cam cover; Sticking turbo vanes and limp mode; Air mass meter (MAF) reading low
- [VW Group 2.0 TDI common rail (EA189)](https://ipacen.com/known-issues/vw-2-0-tdi-cr-ea189): Intake manifold flap fault (P2015); High-pressure pump failure (Bosch CP4.1); EGR valve and EGR cooler; Blocked particulate filter (DPF); Injector wear and leakage
- [VW Group 1.6 TDI common rail (EA189)](https://ipacen.com/known-issues/vw-1-6-tdi-cr-ea189): Leaking or worn injectors; EGR valve sticking; Particulate filter clogging in town use; Dual-mass flywheel wear
- [BMW N47 2.0 and 1.6 diesel](https://ipacen.com/known-issues/bmw-n47-diesel): Timing chain stretch and guide failure; EGR cooler leaking coolant (recall); Crankshaft pulley (vibration damper) failure
- [Renault/Nissan 1.5 dCi (K9K)](https://ipacen.com/known-issues/renault-1-5-dci-k9k): Big-end bearing spin; Injector failure and starting problems; Turbo failure from oil starvation; Particulate filter and oil level rising
- [PSA/Ford 1.6 HDi and 1.6 TDCi (DV6)](https://ipacen.com/known-issues/psa-ford-1-6-hdi-tdci-dv6): Leaking injector washers ("black death"); Turbo failure from a blocked oil feed; Particulate filter additive running out
- [Fiat/Opel/Suzuki 1.3 Multijet, CDTI and DDiS](https://ipacen.com/known-issues/fiat-opel-1-3-multijet-cdti): Oil level rising (diesel in the oil); Timing chain stretch; EGR valve clogging
- [Mercedes-Benz OM651 2.1 and 1.8 CDI](https://ipacen.com/known-issues/mercedes-om651): Injector failure on early engines (Delphi piezo); Injector seal leaks and seized injectors; Split charge-air hoses and limp mode
- [Toyota 2.0 and 2.2 D-4D (1AD, 2AD)](https://ipacen.com/known-issues/toyota-2-0-2-2-d-4d-ad): Head gasket failure and high oil consumption; EGR and intake carbon build-up
- [Mazda 2.2 diesel (MZR-CD and Skyactiv-D)](https://ipacen.com/known-issues/mazda-2-2-diesel): Oil level rising from diesel dilution; Injector seal leaks and carbon in the oil (MZR-CD); Timing chain stretch
- [VW Group 1.2 and 1.4 TSI (EA111, timing chain)](https://ipacen.com/known-issues/vw-1-2-1-4-tsi-ea111): Timing chain stretch and tensioner; Cracked pistons on the high-output 1.4 TSI; Turbo wastegate rattle (1.4 TSI 122–125 hp)
- [VW Group 1.8 and 2.0 TSI/TFSI (EA888, generations 1 and 2)](https://ipacen.com/known-issues/vw-audi-1-8-2-0-tfsi-ea888): High oil consumption (piston rings); Timing chain tensioner failure and chain jump; Crankcase breather (PCV) valve failure; Carbon build-up on the intake valves
- [PSA/Stellantis 1.0 and 1.2 PureTech (EB)](https://ipacen.com/known-issues/psa-1-2-puretech): Timing belt breaking down in the oil; High oil consumption
- [Ford 1.0 EcoBoost (three-cylinder)](https://ipacen.com/known-issues/ford-1-0-ecoboost): Coolant leaks and overheating; Timing belt in oil wearing early
- [BMW/PSA 1.6 THP and VTi "Prince" (N14, N18, EP6)](https://ipacen.com/known-issues/bmw-psa-1-6-prince): Timing chain stretch, tensioner and guides; Oil consumption and carbon build-up; High-pressure fuel pump wear (turbo engines); Coolant leaks: water pump and thermostat housing
- [Renault/Nissan 1.2 TCe and DIG-T (H5Ft, HRA2DDT)](https://ipacen.com/known-issues/renault-nissan-1-2-tce): High oil consumption; Timing chain stretch after running low on oil
- [Hyundai/Kia 2.0 and 2.4 Theta II](https://ipacen.com/known-issues/hyundai-kia-theta-ii): Connecting-rod bearing failure; Carbon build-up on the intake valves (GDI)
- [Fiat 1.4 MultiAir and 0.9 TwinAir](https://ipacen.com/known-issues/fiat-1-4-multiair-0-9-twinair): MultiAir actuator failure; Dual-mass flywheel and clutch judder (0.9 TwinAir)
- [Volvo 5-cylinder petrol (2.0–2.5, turbo and non-turbo)](https://ipacen.com/known-issues/volvo-5-cylinder-petrol): Clogged crankcase ventilation (oil trap); Electronic throttle module failure (older cars); Timing belt, tensioner and idler pulley
- [Hyundai/Kia 1.6 GDI (Gamma)](https://ipacen.com/known-issues/hyundai-kia-1-6-gdi-gamma): Carbon build-up on the intake valves; Oil consumption and piston or bearing damage
- [Toyota/Lexus 1.8 Hybrid (2ZR-FXE)](https://ipacen.com/known-issues/toyota-lexus-1-8-hybrid): Clogged EGR system, misfire and head gasket damage; Weak 12 V auxiliary battery; Inverter coolant pump failure

## Common fault codes
- [P0016: Crankshaft Position – Camshaft Position Correlation (Bank 1 Sensor A)](https://ipacen.com/codes/P0016)
- [P0087: Fuel Rail/System Pressure – Too Low](https://ipacen.com/codes/P0087)
- [P0101: Mass or Volume Air Flow "A" Circuit Range/Performance](https://ipacen.com/codes/P0101)
- [P0128: Coolant Thermostat (Coolant Temperature Below Thermostat Regulating Temperature)](https://ipacen.com/codes/P0128)
- [P0171: System Too Lean (Bank 1)](https://ipacen.com/codes/P0171)
- [P0299: Turbocharger/Supercharger "A" Underboost Condition](https://ipacen.com/codes/P0299)
- [P0300: Random/Multiple Cylinder Misfire Detected](https://ipacen.com/codes/P0300)
- [P0335: Crankshaft Position Sensor "A" Circuit](https://ipacen.com/codes/P0335)
- [P0401: Exhaust Gas Recirculation "A" Flow Insufficient Detected](https://ipacen.com/codes/P0401)
- [P0420: Catalyst System Efficiency Below Threshold (Bank 1)](https://ipacen.com/codes/P0420)
- [P2463: Diesel Particulate Filter Restriction – Soot Accumulation](https://ipacen.com/codes/P2463)
- [U0100: Lost Communication With ECM/PCM "A"](https://ipacen.com/codes/U0100)

## Optional
- [Full fault code reference in one file](https://ipacen.com/llms-full.txt)
- [Sitemap](https://ipacen.com/sitemap.xml)