P0322: How to Diagnose & Fix — Ignition/Distributor Engine Speed Input Circuit No Signal

B6/B7 A4 owners who set P0322 almost always buy an engine speed sensor (G28) first, and a share of them are back on the forums a week later with the same code and the same no-start. The reason is that on this platform the failure is often the circuit rather than the pickup. The G28 lives at the bellhousing above the flywheel ring gear, and its lead runs up the back of the engine through a zone that sees exhaust heat, oil weepage and constant vibration from engine rock. Insulation hardens and chafes, a conductor breaks inside the loom, or the connector's female terminals spread and oxidise - and any of those gives the ECM the same result as a dead sensor: zero pulses, and P0322 stored as no signal. Ross-Tech's guidance for 16706/P0322 is explicitly to check the wiring to and from the sensor and the ECM before condemning the part, and at least one documented case traced the fault to a broken signal wire far from the sensor, up in the main loom near the ECU under the scuttle panel. Owners describe an engine that cranks at normal speed and never fires, sometimes preceded by weeks of hot-restart hesitation or a stall pulling into a parking space. Both the 1.8T and the 2.0T FSI are affected, and the code often shows up alongside P0321 (implausible/erratic signal) when the circuit is intermittently making contact rather than fully open - that pairing is a strong hint that the problem is a connection, not the sensor element. On the A4 there is also a purely mechanical version of the same complaint: a replacement sensor that is not pushed fully into its bore, or whose retaining bolt is left loose, sits at too large an air gap and reproduces the no-signal fault straight after the repair. What makes this pattern worth calling out separately is the money it wastes - the sensor is cheap, but diagnosis by parts substitution is not.

On the Mk4-generation Jetta the crankshaft position sensor is called the Engine Speed Sensor, or G28 in VW's component code. It is a magnetic pickup bolted into the bellhousing on the underside of the engine/transmission joint, where it reads the teeth of the flywheel/flexplate ring gear and hands the ECM the only true crankshaft speed and position reference the engine has. That location bakes it: the sensor sits inches from the exhaust and the transmission case, and after a decade of heat cycling the winding inside opens up or the potted body cracks. When the pickup goes fully open the ECM sees nothing on the circuit and stores P0322 (VCDS shows the same fault as 16706 - Engine Speed Sensor (G28): No Signal). The classic complaint pattern is temperature-dependent and progresses in a recognisable way. The car starts fine cold and drives normally, then after twenty or thirty minutes at operating temperature it cuts out at a stoplight or on deceleration as if the key had been switched off. It cranks briskly afterwards but will not fire, and the tachometer needle stays flat on zero the whole time it is cranking - a flat tach while cranking is the single most diagnostic symptom, because the cluster gets its RPM from the same signal. Let it sit thirty to sixty minutes and it starts and drives again, which is why owners chase fuel pumps and ignition switches first. Eventually the sensor fails outright and the car never restarts. The same sensor and the same failure appear across the sibling Mk4 cars - Golf, New Beetle - and on both the 2.0L 8-valve (AEG/AVH/BEV/BBW) and the 1.8T, and again on the later 2.5L five-cylinder cars. The secondary cause worth ruling out before buying parts is the circuit rather than the sensor. The G28 pigtail runs along the bellhousing and can chafe on the subframe or be cooked by exhaust heat, and the connector picks up oil film and corrosion in that location; a broken wire or a spread terminal produces the identical no-signal fault, which is why forum threads are full of owners who fitted a new sensor and still had a no-start.

The 3.9/5.2/5.9 Magnum uses a camshaft position sensor inside the distributor plus a crankshaft position sensor on the bell housing. These sensors are heat-sensitive and fail intermittently — the engine stalls or dies when hot and refuses to restart until it cools, or cranks-but-won't-start with no other symptom. Corroded/loose sensor connectors cause the same behavior.

The first-generation Touareg logs P0322 when the G28 engine speed sensor stops feeding the engine control module. On the 3.2L VR6 and on the V6 TDI the sensor sits low on the engine at the block/bellhousing area, in one of the hottest and most oil-soaked parts of the bay, and it is notoriously awkward to reach - owners report having to put the steering on full lock and work up from underneath to get a hand on it. Heat and oil film degrade the pickup over time; when it opens up, the ECM loses its crank reference completely and both fuel injection and (on the petrol VR6) spark stop. The symptoms are unambiguous once you know what to look for. The truck cranks strongly - batteries and starter are fine - but never catches, and a scan tool shows engine speed pinned at zero during cranking. Before the outright failure most owners get a warning period: the fault is stored as intermittent (16706 - Engine Speed Sensor (G28): No Signal - Intermittent), the vehicle occasionally stalls at idle or on the overrun, or it takes an unusually long crank to fire, particularly once hot. Because a Touareg no-start also looks like a fuel-pump, immobiliser or battery-drain problem - all of which the platform is prone to - the crank sensor is frequently the third or fourth thing tried, after a lot of money has already been spent. A second, cheaper cause is the sensor connector and pigtail. The connector sits where oil weeps from the sump and cam-cover seams collect, and a contaminated or partially unlatched connector produces exactly the same no-signal fault as a dead sensor. Ross-Tech's own guidance for this code is to check the wiring to and from the sensor and the engine control module for damage from engine oil or coolant before condemning parts.