Diagnostic Test
TESTING FOR A SHORT TO GROUND USING AN OHMMETER
NOTE:
Before measuring the resistance of any circuit, first measure the resistance between the two leads of the multimeter. Take this value and subtract it from the value recorded when measuring the resistance of the circuit being checked (The meter leads can add 0.5 ohm or more of total resistance).
- Turn the ignition off.
- Disconnect the wire harness connectors from the module and component for the suspected circuit being shorted to ground.NOTE:
Check connectors - Clean/repair as necessary.
- With the component wire harness connectors disconnected, use a meter set to measure Ohms (Ω), and measure the resistance between the circuit and a known good ground.
- Use the negative lead of the meter and touch a known good ground.
- Use the positive lead of the meter and carefully probe the circuit suspected of having the short.
Is the resistance to ground below 10k ohms ?
Yes
- Repair the short to ground. Use the wiring diagram as a guide to follow the path of the circuit.
- One method to help isolate the short is to disconnect any in-line connectors that the circuit being tested runs through and measure for the short again. If the short goes away, the short is on the other side of the in-line connector.
No
- The circuit is not shorted to ground or the condition that originally caused the short may not be present at this time. Continue to measure the resistance, wiggle the wire harness and connectors while checking for an intermittent short.
- Use the wiring diagram as a guide to trace the circuits and look for any in-line connectors where the short could occur intermittently.
- Look for any chafed, pierced, pinched, or partially broken wires.
- Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the related wire harness connectors.
- Perform any Technical Service Bulletins (TSBs) that may apply.