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 Jeep Cherokee LimitedFACTORY OEM SERVICE PROCEDURE
5.9L Primary Ignition
- Turn ignition on. Using voltmeter, check voltage between positive terminal of ignition coil and ground. If voltage is 5.5-6.5 volts, go to next step. If voltage is not 5.5-6.5 volts, check ignition switch, radio capacitor, connections and coil. Ensure resistance wire, between ignition switch and coil, is 1.3-1.4 ohms.
- Turn ignition switch to START position while observing voltmeter. Battery voltage should exist. If battery voltage is not present, check wire attached to starter solenoid "I" terminal. Check starter solenoid for proper operation.
- Disconnect 2-wire connector at ignition module. Turn ignition on. Ensure battery voltage is present at Yellow wire. Turn ignition switch to START position. Ensure battery voltage is present at Green wire. Repair or replace if necessary.
- Disconnect 4-wire connector at ignition module. Resistance between terminals "C" (White wire) and "D" (Light Blue wire) should be 400-800 ohms. If resistance is not 400-800 ohms, check wiring and pick-up coil in distributor.
- Ensure terminal "B" (Black wire) has continuity to ground. Repair or replace if necessary. Ensure terminal "A" (Green wire) has continuity to negative side of coil. If terminal "A" (Green wire) is shorted to ground, repair wire and replace ignition module.
- Reconnect ignition module connectors. Repeat SECONDARY SPARK CHECK . If there is still no spark, replace ignition module.
Factory Service Tools
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Disclosure: Verified tool recommendations may earn an affiliate commission at no 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.
Rather have a pro handle this?
A certified mobile mechanic comes to your home or office. They bring the tools, you stay comfortable. No tow truck, no waiting room, no surprises.
Comes to youSame-day available12-month warranty
Get a Free QuoteNo obligation. See pricing before you book.