OBD-II Code P0392 — What It Means & How to Fix It

What Does This Error Mean?

P0392 means the PCM is measuring a voltage on the camshaft position sensor B signal circuit on Bank 2 that is lower than the minimum acceptable threshold. Sensor B is the exhaust camshaft sensor. Bank 2 is the engine side without cylinder 1. A low signal usually points to a bad sensor, a short to ground in the wiring, or a missing power supply.

Affected Models

All 1996+ V6, V8, and V10 vehicles with DOHC engines and exhaust camshaft position sensors
Common in Toyota and Lexus V6 models — Camry, ES350, Highlander, and 4Runner
Common in Honda and Acura V6 with i-VTEC systems
Common in Nissan and Infiniti V6 engines with VVEL or CVTCS systems
Common in Ford and GM DOHC V6 and V8 engines

Common Causes

Camshaft position sensor B on Bank 2 with an internally shorted signal element
Short circuit to ground in the Bank 2 cam sensor B signal wire
Open or broken wire in the sensor reference voltage supply circuit
Corroded or damaged sensor connector with poor pin contact
PCM signal input circuit damaged on the Bank 2 cam B channel (rare)

How to Fix It

With the sensor connector disconnected and the ignition on, measure the reference voltage on the sensor's supply pin. It should read approximately 5V on most vehicles. A reading well below 5V indicates a supply problem or a short to ground on the supply wire.

Always disconnect the sensor before measuring. A failed sensor with an internal short can pull the supply voltage down and give you a false impression that the wiring is the problem.
Measure the voltage on the signal wire with the sensor still disconnected and the ignition on. It should read close to 0V or follow your factory spec with the sensor unplugged. A reading near 0V is normal. A reading stuck at or near 0V with the sensor connected and engine running confirms a low-signal fault.

The key here is measuring with the sensor disconnected to isolate whether the low reading is from the wire or from the sensor. This tells you which component to focus on.
Inspect the signal wire from the Bank 2 cam sensor B all the way back toward the PCM. Look for spots where the wire could be contacting a ground point — chassis metal, the block, an exhaust component, or another grounded wire. A pinched wire is the most common cause of a short to ground.

Trace the harness carefully in areas where it passes through grommets or is secured with clamps near metal edges. These are the spots most prone to insulation damage.
Replace the camshaft position sensor B on Bank 2 if the wiring checks are clean. A sensor with an internal short to ground will produce a persistently low signal regardless of what the wiring looks like. Use a quality part matched to your exact vehicle.

Confirm the part is correct for Bank 2 and for the exhaust camshaft. Use your VIN when ordering to ensure the right calibration for your engine.
After replacement, clear all stored codes and perform a test drive. Monitor the cam sensor signal on live data if your scanner supports it. If P0392 returns on a new sensor with clean wiring, have a technician check the PCM input circuit directly.

A PCM input channel that was damaged by a previous short to ground will continue to read a low voltage even after the short is repaired. This is a low-likelihood but real possibility on vehicles with a history of wiring issues.

When to Call a Professional

If sensor replacement and wiring checks do not resolve P0392, the PCM input circuit may be damaged. Measuring exact voltages at the PCM harness connector requires a wiring diagram and a digital multimeter, and interpretation is easier with professional training. Diagnosis typically costs $80-$150. PCM replacement or repair is a last resort but can cost $300-$900 or more.

Frequently Asked Questions

What does low input mean versus no signal?

Low input means the PCM is receiving a signal voltage, but that voltage is below the minimum threshold for a valid reading. No signal (which would set a different code) means the PCM gets nothing at all. Low input is usually caused by a weak sensor, a partial short to ground, or a supply voltage problem. No signal is usually caused by a completely dead sensor, a broken wire, or a missing power supply.

Can I drive with P0392 active?

The car will likely run, but with reduced performance and potentially incorrect variable valve timing on Bank 2. You will probably notice hesitation, rough idle, or slightly lower fuel economy. P0392 is not immediately dangerous, but driving with it long-term can stress other engine components. Get it diagnosed within a week or so.

How is P0392 different from P0390?

P0390 is a general circuit fault for the Bank 2 cam sensor B — it could be any electrical problem in the circuit. P0392 specifically indicates the signal voltage is too low — which narrows it down to a short to ground, a weak sensor, or a supply voltage problem. P0392 gives you more information about the nature of the electrical fault.