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.
Circuit/System Testing (ECM)
2006 Chevrolet Suburban C1500, 5.3 ZSECTION Circuit/System Testing (ECM)
WARNING: This page is about a different car, the 2009 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
- Engine running, accessories OFF, measure and record the battery voltage at the battery terminals. The voltage should be between 12.6 and 15.0 volts.
- If not within the specified range, refer to Charging System Test .
- Ignition OFF, disconnect the harness connectors at the ECM.
- Ignition OFF and scan tool disconnected, open and close the driver door, and wait 30 seconds. Test for less than 5 ohms between the appropriate ground circuit terminal listed below and ground.
- Terminal 73 X1 (LZ4)
- Terminal 73 X2 (LAT, LE5, LY7)
- If greater than the specified range, test the ground circuit for an open/high resistance.
- Verify that a test lamp illuminates between the B+ circuit terminal 20 X1 and ground.
- If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
- Ignition OFF, connect a 3A fused jumper between the appropriate PWR/TRN relay control circuit terminal listed below and ground.
- Terminal 13 X1 (LE5)
- Terminal 40 X1 (LY7)
- Terminal 59 X1 (LZ4)
- Terminal 40 X2 (LAT)
- Ignition ON, verify that a test lamp illuminates between the appropriate ignition circuit terminals listed below and ground:
- Terminal 3 X1 (LE5)
- Terminal 18 X1 (LAT, LY7, LZ4)
- Terminal 19 X1 (LAT, LE5, LY7, LZ4)
- Terminal 47 X1 (LZ4)
- Terminal 73 X1 (LE5)
- Terminal 13 X2 (LAT, LY7)
- If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.
- If all circuits test normal, replace the ECM.
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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.