P2B37

Code

Generic P — Powertrain

A Camshaft Profile Actuator B Control Circuit Low Bank 2

Brand: Generic

Type: P — Powertrain

Views: UK: 30 EN: 33 RU: 32

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Causes

Short to ground in the actuator control wire (harness damage, pin contact to chassis).
Faulty camshaft profile actuator (VVT solenoid) — internal short, stuck, or open coil.
Poor or corroded connector or pin at the actuator or at the engine harness.
Low battery or poor charging system voltage during test.
Blown fuse or faulty relay supplying the actuator circuit.
Faulty PCM/ECU driver for the actuator control.

Symptoms

Malfunction Indicator Lamp (MIL)/Check Engine Light on.
Reduced engine performance or torque, hesitation on acceleration.
Rough idle or misfire-like symptoms under some conditions.
Reduced fuel economy and increased emissions.
Stored camshaft timing or VVT-related trouble codes; limp performance mode on some vehicles.

What to check

Read freeze frame and related codes with a scan tool; note engine speed, oil temperature, battery voltage at fault time.
Check battery and charging voltage (should be ~12–14.5 V).
Visually inspect actuator connector, pins and wiring for damage, corrosion, chafing or pinched wires.
Check oil level and condition (very dirty or low oil can affect VVT operation).
Check fuses/relays related to engine control/VVT circuits.
Back-probe the actuator connector to measure control and supply voltages with ignition ON and engine running (use oscilloscope for PWM).

Signal parameters

Supply/reference circuit: typically battery voltage (~11–14.5 V) on the power/reference pin with ignition ON — verify per vehicle manual.
Control circuit: PCM drives the actuator with a PWM signal; a ‘low’ fault means the control line is sitting near 0 V or is shorted to ground.
Expected resistance of a typical VVT solenoid coil: commonly about 6–30 ohms (manufacturer-specific) — consult service data.
PWM characteristics: frequency and duty vary by manufacturer; common ranges ~50–250 Hz — use scope to view waveform.
If the control line measures near 0 Ω to ground with the connector disconnected, suspect a short to ground in the harness or ECU driver fault.

Diagnostic algorithm

Connect a capable scan tool. Record freeze frame, all related codes and live data (camshaft position, commanded vs actual, actuator duty).
Verify battery/charging voltage. If low, charge/replace battery and retest.
Visually inspect the Bank 2 Camshaft Profile Actuator B connector and wiring for damage, corrosion, pin deformation, or oil contamination. Repair any obvious problems.
With ignition ON (engine OFF) back-probe the actuator connector: verify reference/power pin battery voltage and measure control pin voltage. Expect reference ~12 V and control not hard-grounded; consult service data for exact pinout.
Start engine and observe control pin with a scope if available: confirm PCM is commanding a PWM waveform. If command is present but actuator does not respond, suspect actuator or mechanical seizure.
With connector disconnected, measure resistance from control pin to chassis ground — if near 0 ohms, there is a short to ground in harness or ECU driver.
Measure coil resistance across the actuator pins (with connector disconnected) and compare to spec. If out of range, replace the actuator.
If wiring and actuator check good, perform voltage drop and continuity tests between actuator connector and PCM connector. Repair any open/shorts.
If short/driver fault located at PCM, confirm with bench tests and wiring verification before replacing PCM. Consider swapping with known-good actuator or using manufacturer repair data.
After repairs, clear codes and perform functional test/road test; verify code does not return and cam timing behavior is correct.