Pickup Coil Repair: How to Test the Pickup Coil Signal
There are many reasons why an engine won't start. And in the case of cars with ignition coil systems, one cause is that of pickup coil failure. A faulty pickup coil or coil wire can prevent the switching signals coming from the ignition module to reach the ignition coil, although the module itself can also be faulty and unable to send the signal at all.
To determine whether the pickup coil or the ignition module is at fault, you will need to verify if the pickup coil is sending a signal through the following means:
Difficulty level: Easy
What you'll need:
- Screwdriver set (optional)
- Soldering wire and iron (optional)
- Heat shrink tubing (optional)
Step 1: Set the car's transmission to park and kill the engine. Detach the battery cables from the posts of the battery and set them aside.
Step 2: Locate the pickup coil. Depending on the vehicle, the coil is usually located beside the engine on top of the ignition module.
Step 3: Check the wires connected to the pickup coil and their respective contact points. Take note of any signs of cuts or deterioration along the length of the wire and corrosion in the contacts. Small to medium cuts may still be fixed by soldering the wires and covering it with heat shrink tubing, but severely damaged wires need to be replaced. In the case of corroded contacts, you can remove the rust using sandpaper and contact cleaner.
Step 4: Disconnect the pickup coil connector at the ignition control module. You can check with your car's service manual to determine where this is located in the module. The connectors are usually held in place by screws or plastic tabs, so remove them accordingly.
Step 5: Insert a test lead into any of the female terminals of the coil. Be careful not to shove the leads in too deep to prevent damaging the terminals and nearby components.
Step 6: Connect the black test lead of the multimeter to one of the test leads inside one terminal.
Step 7: Connect the red test lead to the other female terminal.
Step 8: Reconnect the battery cables to their respective posts in the battery.
Step 9: Have someone switch on the engine while you observe the readings in the multimeter. Ideally, the AC voltage on the multimeter should read between .3 bolts and 1/8 volts AC.
As a rule of thumb, if the multimeter registered the volts indicated above, it means that the pickup coil is working properly and the ignition module is likely to be the source of the problem. In such cases, you will need to replace the ignition module. However, if the multimeter does not display the indicated volts, check the wires again and redo the test. If the test still shows the same results, the pickup coil is malfunctioning and needs to be replaced.
Note: Wear protective clothing including eyewear and insulated gloves before starting. Even if the pickup coil is no longer working and the battery detached from the system, there may still be enough energy left in the lines to cause injury from electric shock.