Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Scan Tool Data Definitions
- Battery Voltage Signal
-
The scan tool displays 0-20 Volts. The scan tool displays the voltage as received by the Module or the 72-08 battery voltage message from the BCM over class 2 lines.
- Crank Request Signal
-
The scan tool displays Yes/No. The scan tool displays No until the ignition is placed into the START position then Yes is displayed.
- GEN F-Terminal Signal
-
The scan tool displays 0-100%. The scan tool displays 0-10% until the engine is started and the PCM receives a signal from the generator then OK is displayed.
- GEN L-Terminal Circuit Status
-
The scan tool displays Incomplete, Short Gnd/Open, Short to B+ or OK. The scan tool displays the status of the GEN L-Terminal circuit.
- GEN L-Terminal Command
-
The scan tool displays %. The scan tool displays the percentage of the GEN L-Terminal signal.
- GEN L-Terminal Signal Command
-
The scan tool displays On/Off. The scan tool displays Off until the engine is running, then displays On when the engine is running.
- Idle Boost Level
-
The scan tool displays the current engine idle boost level as commanded by the ECM.
- Ignition 1 Signal
-
The scan tool displays 0-20 Volts. The scan tool displays the voltage as received on the Ignition 1 circuit to the PCM.
- IMS
-
The scan tool displays Drive 3, Drive 4\Drive 3, Park\Reverse, Reverse, Drive 3\Drive 2, Drive 2, Park, Invalid, Neutral\Drive 4, Drive 4, Neutral, Reverse\Neutral, Drive 1, Drive 2\Drive 1, or Open. The scan tool displays the position of the transmission range switch.
- Starter Relay Circuit Status
-
The scan tool displays Incomplete, Short Gnd/Open, Short to B+ or OK. The scan tool displays the status of the starter relay circuit.
- Starter Relay Command
-
The scan tool displays ON/OFF. The scan tool displays Off until engine start has been requested, then it reads On.
- TR Sw.
-
The scan tool displays Park, Reverse, Neutral, Invalid, Drive 5, Drive 4, Drive 3, Drive 2 or Drive. The scan tool displays the position of the transmission range switch.
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.