Mercury 2002 EFI 150 EST CODES

[Catfishhunter]

I have a 2002 mercury EFI 150hp that goes into guardian mode randomly and when I had the codes checked it had codes EST1, EST3 and EST5. Would anyone know the issue. Thanks

 

[AllDodge]

EST1 - Specifically indicates an issue with the trigger lead for cylinder #1, potentially related to the PCM or crank sensor.
EST3 - Often indicates a fault in the signal from the ECM to the ignition driver module
EST5 - The circuit from the PCM to the ignition coil is open (no continuity), often caused by wiring issues, faulty coils, or spark plug wire problems.

Most likely there are bad connections. Look for corrosion first

 

[Catfishhunter]

EST1 - Specifically indicates an issue with the trigger lead for cylinder #1, potentially related to the PCM or crank sensor.
EST3 - Often indicates a fault in the signal from the ECM to the ignition driver module
EST5 - The circuit from the PCM to the ignition coil is open (no continuity), often caused by wiring issues, faulty coils, or spark plug wire problems.

Most likely there are bad connections. Look for corrosion first

I have checked all grounds and they were all very clean would you know where else to look thank you

 

[AllDodge]

Remove the ground cable and than start disconnecting other cable connectors. The one on the crank sensors, the ECM and others. The ground cable is removed because you don't want any sparks when removing other connectors

 

[AllDodge]

EST means Electronic Spark Timing, so the ECM is seeing that there is an issue with it

 

[Catfishhunter]

Remove the ground cable and than start disconnecting other cable connectors. The one on the crank sensors, the ECM and others. The ground cable is removed because you don't want any sparks when removing other connectors

Okay I will try this thank you again