Circuit/System Verification
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2011 GMC Yukon XL, 2011 GMC Yukon, 2011 Chevrolet Tahoe, 2011 Chevrolet Suburban, and 2011 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
- Most vehicle systems will go to sleep within 30 min but it can take up to 2 h before all systems power down allowing the parasitic draw test to pass. An occasional increase in the parasitic draw is normal as long as it returns within 1 s.
- Closing the door latches/ajar switch while leaving the doors open is recommended, this allows the vehicle systems to perform in a "doors closed" mode while allowing vehicle interior access that may be needed to complete the diagnostic steps.
- Locking doors will arm the vehicle content theft deterrent system if equipped. Failure to arm the system may cause a theft system fault to not be present during testing.
- There are many things that can prevent the vehicle from completely going to sleep and passing the parasitic draw test. Make sure all the conditions listed below are met before performing the parasitic current draw test.
- Ignition OFF
- Key out of the ignition switch - when not equipped with keyless access and start
- Retained Accessory Power OFF - open and close the driver door after ignition OFF
- Scan tool not communicating with a vehicle control module - in some cases it may need to be disconnected from the DLC
- All access doors closed
- Headlamps OFF - auto headlamps disabled
- Any delay lighting OFF
- If equipped with an under hood lamp disable it
- HVAC after blow OFF
- Any accessory that can work with ignition OFF inactive or OFF
- Wait up to 2 min or longer, after all other listed conditions are met
Using an Inductive Pickup Probe
- Connect an inductive pickup probe to the negative battery cable that can read down to 1 mA.
- Ignition OFF, as the vehicle systems shut down test for less than 30 mA of parasitic current drain.
- If greater than the specified range, refer to Circuit/System Testing below.
Using the EL 38758 Parasitic Draw Test Switch
- Ignition OFF, disconnect the battery negative cable from the battery. Refer to Battery Negative Cable Disconnection and Connection .
- Turn the EL 38758 switch knob to the OFF position.
- Install the male end of the EL 38758 switch to the battery ground terminal.
- Install the battery negative cable to the female end of the EL 38758 switch.
- Turn the EL 38758 switch knob to the ON position.
- Road test the vehicle and activate all of the accessories such as the radio and air conditioning.
- Ignition OFF, connect a 10 A fused jumper wire to the test switch tool terminals.
- Turn the EL 38758 switch knob to the OFF position. The current now flows through the jumper wire.
- Check the fuse in the jumper wire. The fuse should be OK.
- Failed: If the jumper wire fuse is blown, refer to Circuit/System Testing below.
- Passed
- Turn the EL 38758 switch knob to the ON position. Remove the fused jumper wire.
- Connect a DMM set to the 10 A DC scale between the test switch tool terminals.
- Turn the EL 38758 switch knob to the OFF position. The current now flows through the DMM.
- As the vehicle systems shut down test for less than 30 mA of parasitic current drain.
- If greater than the specified range, refer to Circuit/System Testing below.
WARNING:
Refer to Battery Disconnect Warning .
CAUTION:
When a fused jumper wire or digital multimeter is connected to the test switch terminals, always turn the test switch ON before opening any access door, turning the ignition on, or turning any accessory on. This is to prevent damaging the jumper wire or digital multimeter fuse.
NOTE:
The switch knob on the EL 38758 switch is marked ON and OFF. When the switch knob is in the ON position, the circuit is closed and electrical current will pass through the switch. When the switch knob is in the OFF position, the circuit is open and electrical current will not pass through the switch.