E018

ECM Code E018:

DFI Crank Circuit:

DESCRIPTION:

The crank input to the ECM is an ON/OFF signal that comes from the starter solenoid, through the 3A crank fuse then to pin B3 of the ECM. During crank, the signal is battery voltage, at all other times the signal is at 0 volts.

Code EO18 is set if the ECM detects the engine running at 800 RPM or greater, without having the crank input go to system voltage.

TEST CONDITIONS:

1. Engine speed changed from 0 RPM to greater than or equal to 800 RPM while in park or neutral.

FAILURE CONDITIONS:

No crank signal has been received by the ECM since the last time that engine speed was 0 RPM, (Engine started, ECM didn't register a crank signal).

ACTION TAKEN:

1. ECM turns on "SERVICE ENGINE SOON" telltale.
2. ECM commands BCM to display "SERVICE SOON" message on CCDIC.
3. Code is stored as current for entire key cycle.

NOTES ON FAULT TREE:

1. Do not use this procedure if EO18 is a history code. See NOTE ON INTERMITTENTS.

2. If CKT 806 becomes grounded, the crank fuse will blow when the engine is cranked.

3. This branch of the fault tree is to test for ECM or BCM shorting crank input to ground.

4. Voltage signal to crank fuse comes from the ignition switch to the theft starter interrupt relay to the P/N switch to the crank fuse. This branch checks for opens between the crank fuse and the starter solenoid.

Remove the crank fuse and use an ohmmeter to check continuity on CKT 806 from the crank fuse to ECM pin B3. Check for intermittent opens while manipulating wiring. If code E018 doesn't set immediately after cranking, check for plug wires arcing, loose engine grounds or other sources of Electromagnetic Interference (EMI). Large transient voltage surges can "Erase" the crank signal from the ECM's memory and cause code E018 to set while driving.