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
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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 body control module (BCM) over class 2 lines.
- Clutch Start Switch (If equipped)
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The scan tool displays Released/Applied. The scan tool displays the position status of the clutch start switch.
- Crank Request Signal
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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
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The scan tool displays 0-100%. The scan tool displays 0-10% until the engine is started and the engine control module (ECM) receives a signal from the generator then OK is displayed.
- GEN L-Terminal Circuit Status
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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 Signal Command
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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
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The scan tool displays amps. The scan tool displays the current engine idle boost level as commanded by the ECM.
- IMS
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The scan tool displays Invalid, Drive 3\Drive 2, Drive 2, Reverse\Neutral, Neutral, Drive 5, Park\Reverse, Park, Drive 3, Drive 4\Drive 3, Reverse, Park\Reverse, Drive 5\Drive 4 or Drive 4. The scan tool displays the position of the transmission range switch.
- Ignition 1 Signal
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The scan tool displays 0-20 Volts. The scan tool displays the voltage as received on the ignition 1 circuit to the ECM.
- Ignition Accessory Signal
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The scan tool displays On/Off. The scan tool displays if the ignition 0 signal is On or Off.
- PNP Switch (If equipped)
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The scan tool displays Park/Neutral or In Gear. The scan tool displays the position status of the park neutral position (PNP) switch.
- Run/Crank Relay Command
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The scan tool displays On/Off. The scan tool displays the commanded state of the Run/Crank relay.
- Starter Relay Circuit Status
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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
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The scan tool displays On/Off. The scan tool displays Off until engine start has been requested, then it reads On.
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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.