GM Service Manual Online
For 1990-2009 cars only

Engine Control Module (ECM)

Scan Tool Parameter

Data List

Units Displayed

Typical Data Value

Operating Conditions: Ignition ON, Engine OFF

Ignition 1 Signal

ECM

Volts

Varies

EC Ignition Relay Command

ECM

On/Off

On

EC Ignition Relay Feedback

ECM

Volts

Varies

Crank Request Signal

ECM

Yes/No

No

Starter Relay Circuit S

ECM

OK/Fault

OK

Starter Relay Command

ECM

On/Off

Off

PNP Switch

ECM

Park/Neutral/In Gear

Park/Neutral

GEN L-Terminal Signal Circuit

ECM

On/Off

Off

GEN F-Terminal Signal

ECM

Percent

Varies

Engine Speed

ECM

RPM

Varies

VTD Password Learn Enable

ECM

Yes/No

No

Vehicle Security Status

ECM

Fuel Continue/Fuel Lockout/Fuel Disabled/Learn Timer Active/Fail Enable/ Learn Enable

Varies

VTD Fuel Disable

ECM

Active/Inactive

Inactive

VTD Auto Learn Timer

ECM

Active/Inactive

Inactive

VTD Fuel Disable Until Ignition Off

ECM

Yes/No

No

Instrument Panel Cluster (IPC)

Scan Tool Parameter

Data List

Units Displayed

Typical Data Value

Operating Conditions: Ignition ON, Engine OFF

Security Indicator Comm

IPC

On/Off

Off