P0018 - Crankshaft Position - Camshaft Position Correlation (Bank 2 Sensor 'A')
System
Powertrain (Engine & Gearbox)
Technical Description
The control module has detected a fault in the Crankshaft Position (P0018). Two sensors that should track together deviate beyond tolerance, forcing a fail-safe for safety.
Multimeter Test Points & Nominal Values
| Test Point / Component | Measurement | Nominal Target Range | Test Condition |
|---|---|---|---|
| Crankshaft Position – Coil Resistance | Resistance (Ω) | 200 - 1800 Ω (typically 500 - 1200 Ω) | Sensor disconnected at 20°C |
| Crankshaft Position – Output (AC Voltage) | Voltage (V) | 0.5 - 2.0 V AC at cranking, rising with RPM | During cranking / engine running |
| Insulation Resistance to Ground | Resistance (MΩ) | > 20 MΩ | Sensor pin to chassis ground |
Sensor disconnected at 20°C
During cranking / engine running
Sensor pin to chassis ground
Oscilloscope Waveform Analysis
2 ms/div, 2 V/divPossible Causes
Bank 2 specific:Inspect wiring harness to cylinder bank 2 (radiator/left bank, exposed to vibration and moisture).
Chafed or pinched wiring harness along the signal path to Crankshaft Position
Poor ground connection or excessive voltage drop (> 0.1 V) at the ground point for Crankshaft Position
Defective internal output driver or reference circuit in the control module for Crankshaft Position
Symptoms
Recommended Solution
Cross-swap the component on Bank 2 with Bank 1 to rule out mechanical oil passages and internal timing wear.
Graph both paired sensors simultaneously in scan-tool live data to pinpoint which sensor is diverging.
Verify loaded supply voltage and harness terminal pins at Crankshaft Position.
Check circuit continuity and ground-side voltage drop (< 0.05 V) for Crankshaft Position.
Scope the signal trace during cranking to verify symmetric sine peaks without missing or deformed teeth.
Mechanic's Tip
Inductive VR sensors often test fine cold but develop an open circuit when engine heat expands the internal fine windings. Gently warm the sensor with a heat gun while monitoring resistance to expose thermal open circuits.