Powertrain, generic · Ignition system or misfire

P0390 Camshaft Position Sensor B Circuit Bank 2

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

Camshaft position sensor B is the exhaust camshaft sensor; bank 2 is the side without cylinder 1, so the code only occurs on V and boxer engines with one exhaust cam sensor per bank. P0390 means no or too few exhaust cam pulses arrive from bank 2 while the crankshaft turns. GM's 3.0 twin-turbo V6 (LGW) sets it after 5.5 s without a cam pulse, 4 s of cranking or fewer than 4 pulses in 3 s, after two trips; for GM it collects all circuit faults. GM's 3.6-litre V6 in the Saab 9-4X also counts 800 of 1,000 engine cycles without a pulse. Ford checks the crank-to-cam ratio from 200 rpm within 5 s, and the 2004 Northstar counts missing signal changes up to 16. The bank 2 exhaust phaser then locks in its base position; the engine keeps running on the crank and intake cam sensors. FCA advises saving the synchronisation data before replacing the sensor.

Likely causes

Connector or wiring of the bank 2 exhaust sensor open or corroded (signal, 5 V, ground)
Camshaft position sensor faulty
Oil contamination or leak at the sensor, sensor loose
Tone wheel on the phaser damaged or wrongly fitted after timing chain work
Engine module, or 5 V reference shorted by another sensor

Symptoms

  • Check engine light on
  • Loss of power (bank 2 exhaust cam timing in its base position)
  • Longer cranking
  • Rough idle
  • Higher fuel consumption

Repair estimate

DifficultyMediumDIY possible
Parts and labour€60–300
Time0.5–2 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

camshaft position sensor exhaustcamshaft tone wheelsensor wiringengine control modulecam phaser exhaust bank2

Related codes

P0391P0392P0393P0394P0365P0018

References: gsi.ext.gm.com, saabwisonline.com, newtonnet.co.uk, fordservicecontent.com.