Terrain FWD L4-2.4L (2010)
Diode Test
1. Apply at least 1 mA when performing the diode bias test
2. Display the break over voltage drop (0-3 V) of a forward biased diode
3. Display infinite (O.L. (Over-load)) when a diode is reverse biased
Min-Max Readings
1. Can update at a 1 ms sample rate
2. Saves and displays minimum and maximum values
Note: Circuits which include any solid state control modules, such as the engine control module (ECM), should only be tested with a 10 MOhms or
higher impedance digital multimeter such as the EL-39200.
The EL-39200 instruction manual is a good source of information and should be read thoroughly upon receipt of the DMM as well as kept on hand for
future reference.
A DMM should be used instead of a test lamp in order to test for voltage in high impedance circuits. While a test lamp shows whether voltage is present
if the impedance is low enough, a DMM indicates how much voltage is present. In other words, if there is not enough current, the test lamp will not
illuminate even though voltage is present.
The ohmmeter function on a DMM shows how much resistance exists between 2 points along a circuit. Low resistance in a circuit means good
continuity.
Note: Disconnect the power feed from the suspect circuit when measuring resistance with a DMM. This prevents incorrect readings. DMMs apply such
a small voltage to measure resistance that the presence of voltages can upset a resistance reading.
Diodes and solid state components in a circuit can cause a DMM to display a false reading. To find out if a component is affecting a measurement take a
reading once, then reverse the leads and take a second reading. If the readings differ the solid state component is affecting the measurement.
Following are examples of the various methods of connecting the DMM to the circuit to be tested:
*
Probe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous
monitoring while you perform other operations or test driving. Refer to Probing Electrical Connectors (See: Testing and Inspection/Component
Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit Testing/Probing Electrical Connectors).
*
Disconnect the harness at both ends of the suspected circuit where it connects either to a component or to other harnesses.
*
If the system that is being diagnosed has a specified pinout or breakout box, it may be used in order to simplify connecting the DMM to the circuit
or for testing multiple circuits quickly.
Using Connector Test Adapters
Using Connector Test Adapters
Special Tools
EL 35616 - Terminal Test Probe Kit
For equivalent regional tools, refer to Special Tools (See: Power and Ground Distribution/Tools and Equipment).
Caution: Do not insert test equipment probes (DMM etc.) into any connector or fuse block terminal. The diameter of the test probes will deform most
terminals. A deformed terminal will cause a poor connection, which will result in a system failure. Always use the EL-38125-580 GM Approved
Terminal Release Tool Kit in order to front probe terminals. Do not use paper clips or other substitutes to probe terminals.
When using the EL-38125-580 GM Approved Terminal Release Tool Kit , ensure the terminal test adapter choice is the correct size for the connector
terminal. Do not visually choose the terminal test adapter because some connector terminal cavities may appear larger than the actual terminal in the
cavity. Using a larger terminal test adapter will damage the terminal. Refer to the EL-38125-580 GM Approved Terminal Release Tool Kit label on the
inside of the EL-38125-580 GM Approved Terminal Release Tool Kit for the correct adapter along with the connector end view for terminal size.
Using Fused Jumper Wires
Using Fused Jumper Wires
Special Tools
J 36169-A Fused Jumper Wire
