P2618 critical

Crankshaft Position Signal Output Circuit Low

The P2618 code means the vehicle's onboard diagnostic system has detected: Crankshaft Position Signal Output Circuit Low. This is a critical severity code.

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Keep driving?
No -- stop driving
DIY difficulty
hard
Estimated cost
$100 - $900 (parts and labor)
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Common Symptoms

  • Engine cranks but does not start
  • Erratic tachometer readings
  • Transmission may not shift properly
  • Check engine light on

Probable Causes (Ranked by Likelihood)

  • Short to ground in crank signal output wiring Very High
  • Receiving module internal short pulling signal low High
  • ECM crank output driver shorted Moderate
  • Water intrusion in signal harness Low

Step-by-Step Diagnostic Procedure

  1. Check crank output circuit for short to ground

  2. Isolate receiving modules to find shorted module

  3. Test ECM crank output voltage

  4. Inspect harness for moisture damage or chafing

Frequently Asked Questions

Can a transmission module cause P2618?

Yes. If the transmission control module has an internal short on the crank signal input, it can pull the entire signal low, affecting all connected modules.

How do I isolate which module is causing the short?

Disconnect modules one at a time from the crank signal circuit. When the signal voltage returns to normal, you have found the module with the internal short.

Will P2618 prevent my transmission from shifting?

Yes. Without a valid crank speed signal, the transmission module cannot calculate proper shift points and may default to a single gear.

Sources

This page is built from documented references. Verify against your own service info before repair work.

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