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.
1991 Geo Tracker LSi, AutomaticFACTORY OEM SERVICE PROCEDURE
Code 41, Ignition Signal CKT/No Signal
ECM tach signal is 12 volts, and varies as ignition coil is toggled to ground. ECM uses this signal as a reference to control spark timing. This code is set if there is no signal, or voltage on Brown wire is constant.
NOTE:
Test numbers refer to test numbers on diagnostic chart.
- Checks for B+ on signal line.
- Checks noise suppressor for open.
- Checks for toggling voltage signal.
Factory Service Tools
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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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.