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Home >> Chevrolet >> 2005 >> Malibu Maxx >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 3 (Engine Control System - 2.2L (L61) - Troubleshooting & Diagnosis) >> Troubleshooting >> Powertrain Relay Diagnosis >> Circuit Description

Circuit Description

WARNING: This page is about a different variant/trim than selected.

The powertrain relay is a normally open relay. The relay armature is held in the open position by spring tension. Battery positive voltage is supplied directly to the relay coil and the armature contact at all times. The powertrain control module (PCM) supplies the ground path to the relay coil control circuit, via an internal integrated circuit called an output driver module (ODM). When the PCM commands the relay ON, the relay coil creates an electromagnetic field. This electromagnetic field overcomes the spring tension and pulls the armature contact into the stationary contact of the relay load circuit. The closing of the relay contacts allows current to flow from the battery to the following fuses and relay.

When the ignition switch is turned to the OFF position, power is interrupted to the output driver module in the PCM, and the relay electromagnetic field collapses. This action allows the spring tension pulling on the armature to separate from the relay load circuit contact, which interrupts current flow to the fuses and relay.

If the powertrain relay fails to close the engine will crank, but may or may not run. The class II communications will be available with the use of a scan tool.

The powertrain relay system diagnosis table assumes that the vehicle battery is fully charged. Refer to Battery Inspection/Test in Engine Electrical.

Powertrain Relay Diagnosis

Step Action Values Yes No
Schematic Reference: Power Distribution Schematics in Wiring Systems and Engine Controls Schematics
Connector End View Reference: Power and Grounding Connector End Views and Electrical Center Identification Views in Wiring Systems and Powertrain Control Module (PCM) Connector End Views
1 Did you perform the Diagnostic System Check Vehicle - in Vehicle DTC Information? - Go to Step 2  Go to Diagnostic System Check - Vehicle in Vehicle DTC Information
2
  1. Turn ON the ignition, with the engine OFF.
  2. Remove the underhood junction block cover.
  3. Probe the following fuses with a test lamp that is connected to a good ground. Refer to Troubleshooting with a Test Lamp in Wiring Systems.
    • ETC FUSE
    • EMISSION FUSE
Does the test lamp illuminate on at least one test point of each fuse?		 - Go to Step 3  Go to Step 12 
3
  1. Turn OFF the ignition.
  2. Probe both test points of the ETC fuse at the underhood junction block with a test lamp that is connected to a good ground.
Does the test lamp illuminate on either test point of the fuse?		 - Go to Step 4  Go to Step 39 
4
  1. Turn OFF the ignition.
  2. Remove the powertrain relay from the underhood junction block with theJ 43244  relay puller pliers.Special Tools . Refer to Relay Replacement (Within an Electrical Center) in Wiring Systems.
  3. Probe both test points of the ETC fuse at the underhood junction block with a test lamp that is connected to a good ground.
Does the test lamp illuminate on either test point of the fuse?		 - Go to Step 5  Go to Step 8 
5
  1. Turn OFF the ignition.
  2. Remove the A/C compressor clutch relay from the underhood junction block.
  3. Probe both test points of the ETC fuse at the underhood junction block with a test lamp that is connected to a good ground.
Does the test lamp illuminate on either test point of the fuse?		 - Go to Step 6  Go to Symptoms - Engine Electrical in Engine Electrical
6
  1. Turn OFF the ignition.
  2. Remove the EMISSION fuse from the underhood junction block.
  3. Probe both test points of the ETC fuse at the underhood junction block with a test lamp that is connected to a good ground.
Does the test lamp illuminate on either test point of the fuse?		 - Go to Step 7  Go to Symptoms - Engine Electrical in Engine Electrical
7
  1. Turn OFF the ignition.
  2. Remove the ETC fuse from the underhood junction block.
    3. NOTE: Refer to Test Probe Notice in Cautions and Notices.
  3. Probe the powertrain relay load circuit terminal at the underhood junction block with a test lamp that is connected to a good ground. Refer to Probing Electrical Connectors in Wiring Systems.
Does the test lamp illuminate?		 - Go to Step 36  Go to Symptoms - Engine Electrical in Engine Electrical
8
  1. Turn OFF the ignition.
    2. NOTE: Refer to Test Probe Notice in Cautions and Notices.
  2. Probe the powertrain relay coil control circuit terminal in the underhood junction block with a test lamp that is connected to battery positive voltage.
Does the test lamp illuminate?		 - Go to Step 9  Go to Step 26 
9
  1. Turn OFF the ignition.
  2. Disconnect the powertrain control module (PCM) electrical connector that contains the relay coil control circuit. Refer to Powertrain Control Module (PCM) Replacement .
  3. Probe the powertrain relay coil control circuit terminal at the underhood junction block with a test lamp that is connected to battery positive voltage.
Does the test lamp illuminate?		 - Go to Step 10  Go to Step 32 
10
  1. Turn OFF the ignition.
  2. Disconnect the negative battery cable at the battery. Refer to Battery Negative Cable Disconnect/Connect Procedure in Engine Electrical.
  3. Disconnect the underhood junction block electrical connector that contains the powertrain relay coil control circuit. Refer to Underhood Electrical Center or Junction Block Replacement in Wiring Systems.
  4. Probe the powertrain relay coil control circuit terminal at the underhood junction block electrical connector with a test lamp that is connected to battery positive voltage.
Does the test lamp illuminate?		 - Go to Step 33  Go to Step 11 
11 Test the underhood junction block powertrain relay coil control bus bar circuit for a short to ground. Refer to Circuit Testing in Wiring Systems.
Did you find a condition?		 - Go to Step 36  Go to Intermittent Conditions 
12
  1. Turn OFF the ignition.
  2. Remove the powertrain relay from the underhood junction block with theJ 43244  .Special Tools . Refer to Relay Replacement (Within an Electrical Center) in Wiring Systems.
    3. NOTE: Refer to Test Probe Notice in Cautions and Notices.
  3. Probe the battery positive voltage terminal for the relay coil at the underhood junction block with a test lamp that is connected to a good ground.
Does the test lamp illuminate?		 - Go to Step 13  Go to Step 24 
13
  1. Turn OFF the ignition.
  2. Probe the relay coil control circuit terminal at the underhood junction block with a test lamp that is connected to a good ground.
Does the test lamp illuminate?		 - Go to Step 15  Go to Step 14 
14
  1. Turn ON the ignition, with the engine OFF.
  2. Probe the powertrain relay coil control circuit at the underhood junction block with a test lamp that is connected to a good ground.
Does the test lamp illuminate?		 - Go to Step 18  Go to Step 20 
15
  1. Turn OFF the ignition.
  2. Disconnect the PCM electrical connector that contains the relay coil control circuit from the PCM. Refer to Powertrain Control Module (PCM) Replacement .
  3. Probe the powertrain relay coil control circuit terminal at the underhood junction block with a test lamp that is connected to a good ground.
Does the test lamp illuminate?		 - Go to Step 16  Go to Step 32 
16
  1. Turn OFF the ignition.
  2. Disconnect the negative battery cable at the battery. Refer to Battery Negative Cable Disconnect/Connect Procedure in Engine Electrical.
  3. Disconnect the underhood junction block electrical connector that contains the powertrain relay coil control circuit. Refer to Underhood Electrical Center or Junction Block Replacement in Wiring Systems.
  4. Connect the negative battery cable at the battery.
  5. Probe the powertrain relay coil control circuit terminal at the underhood junction block electrical connector with a test lamp that is connected to a good ground.
Does the test lamp illuminate?		 - Go to Step 34  Go to Step 17 
17 Test the underhood junction block powertrain relay coil control bus bar circuit for a short to voltage. Refer to Circuit Testing in Wiring Systems.
Did you find a condition?		 - Go to Step 36  Go to Step 26 
18
  1. Turn OFF the ignition.
  2. Disconnect the PCM electrical connector that contains the relay coil control circuit. Refer to Powertrain Control Module (PCM) Replacement .
  3. Turn ON the ignition, with the engine OFF.
  4. Probe the powertrain relay coil control circuit terminal at the underhood junction block with a test lamp that is connected to a good ground.
Does the test lamp illuminate?		 - Go to Step 19  Go to Step 32 
19
  1. Turn OFF the ignition.
  2. Disconnect the negative battery cable at the battery. Refer to Battery Negative Cable Disconnect/Connect Procedure in Engine Electrical.
  3. Disconnect the underhood junction block electrical connector that contains the powertrain relay coil control circuit. Refer to Underhood Electrical Center or Junction Block Replacement in Wiring Systems.
  4. Remove the powertrain relay coil control circuit wire terminal from the underhood junction block electrical connector. Refer to Push to Seat Connectors in Wiring Systems.
  5. Connect the electrical connector that contained the powertrain relay control circuit to the underhood junction block.
  6. Connect the negative battery cable at the battery.
  7. Turn ON the ignition, with the engine OFF.
  8. Probe the powertrain relay coil control circuit terminal at the PCM connector with a test lamp that is connected to a good ground. Refer to Probing Electrical Connectors in Wiring Systems.
Does the test lamp illuminate?		 - Go to Step 34  Go to Step 36 
20
  1. Turn OFF the ignition.
  2. Probe the battery positive voltage terminal for the powertrain relay armature at the underhood junction block with a test lamp that is connected to a good ground.
Does the test lamp illuminate?		 - Go to Step 21  Go to Step 24 
21
  1. Turn ON the ignition, with the engine OFF.
  2. Probe the relay coil control circuit terminal at the underhood junction block with a test lamp that is connected to battery positive voltage.
Does the test lamp illuminate?		 - Go to Step 25  Go to Step 22 
22
  1. Turn OFF the ignition.
  2. Disconnect the negative battery cable at the battery. Refer to Battery Negative Cable Disconnect/Connect Procedure in Engine Electrical.
  3. Disconnect the underhood junction block electrical connector that contains the powertrain relay coil control circuit. Refer to Underhood Electrical Center or Junction Block Replacement in Wiring Systems.
  4. Disconnect the PCM electrical connector that contains the powertrain relay coil control circuit from the PCM. Refer to Powertrain Control Module (PCM) Replacement .
  5. Measure the resistance of the powertrain relay coil control circuit from the underhood junction block electrical connector to the PCM electrical connector with a digital multimeter (DMM). Refer to Troubleshooting with a Digital Multimeter in Wiring Systems.
Does the resistance measure greater than the specified value?		 5 Ω Go to Step 35  Go to Step 23 
23 Test the underhood junction block powertrain relay coil control bus bar circuit for a high resistance or an open. Refer to Circuit Testing in Wiring Systems.
Did you find a condition?		 5 Ω Go to Step 36  Go to Step 32 
24 Probe the mounting stud for the battery positive battery cable at the underhood junction block with a test lamp that is connected to a good ground.
Does the test lamp illuminate?		 - Go to Step 36  Go to Symptoms - Engine Electrical in Engine Electrical
25
  1. Turn OFF the ignition.
  2. Connect a 20-amp fused jumper wire between the battery positive voltage terminal for the relay armature at the underhood junction block to the relay load circuit terminal at the underhood junction block. Refer to Using Fused Jumper Wires in Wiring Systems.
  3. Probe the following fuses with a test lamp that is connected to a good ground.
    • ETC FUSE
    • EMISSION FUSE
Does the test lamp illuminate on at least one test point of each fuse?		 - Go to Step 26  Go to Step 36 
26 Measure the resistance from terminal 85 of the relay to terminal 86 with a DMM. Refer to Troubleshooting with a Digital Multimeter .
Does the resistance measure within the specified range?		 70-110 Ω Go to Step 27  Go to Step 37 
27 Measure the resistance from terminal 30 of the relay to terminal 87 with a DMM.
Does the DMM display the specified value?		 infinity Ω Go to Step 28  Go to Step 37 
28 Measure the resistance from terminal 30 of the relay to terminal 85 with a DMM.
Does the DMM display the specified value?		 infinity Ω Go to Step 29  Go to Step 37 
29 Measure the resistance from terminal 85 of the relay to terminal 87 with a DMM.
Does the DMM display the specified value?		 infinity Ω Go to Step 30  Go to Step 37 
30
  1. Connect a 20-amp fused jumper wire from the battery positive cable at the battery to relay terminal 85. Refer to Using Fused Jumper Wires in Wiring Systems.
  2. Connect a jumper wire from the negative battery cable at the battery to relay terminal 86.
  3. Measure the resistance from terminal 30 of the relay to terminal 87 with a DMM.
Does the resistance measure greater than the specified value?		 3 Ω Go to Step 37  Go to Step 31 
31 Test for shorted or poor connections at the powertrain relay location on the underhood junction block. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
Did you find a condition?		 - Go to Step 36  Go to Intermittent Conditions 
32 Test for shorted or poor connections at the PCM electrical connectors. Refer to Testing for Intermittent Conditions and Poor Connections and Micro-Pack 100W Connectors in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 39  Go to Step 38 
33 Repair the short to ground in the relay coil control circuit between the underhood junction block electrical connector and the PCM electrical connector. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 - Go to Step 39  -
34 Repair the short to voltage in the relay coil control circuit between the underhood junction block electrical connector and the PCM electrical connector. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 - Go to Step 39  -
35 Repair the high resistance or an open in the relay coil control circuit between the underhood junction block electrical connector and the PCM electrical connector. Refer to Wiring Repairs in Wiring Systems.
Did you complete the repair?		 - Go to Step 39  -
36 Replace the underhood junction block. Refer to Underhood Electrical Center or Junction Block Replacement in Wiring Systems.
Did you complete the replacement?		 - Go to Step 39  -
37 Replace the powertrain relay. Refer to Relay Replacement (Within an Electrical Center) in Wiring Systems.
Did you complete the replacement?		 - Go to Step 39  -
38 Replace the PCM. Refer to Powertrain Control Module (PCM) Replacement .
Did you complete the replacement?		 - Go to Step 39  -
39
  1. Reassemble the vehicle as necessary.
  2. Replace any open fuses.
  3. Turn OFF the ignition for 30 seconds.
Does the engine start and run?		 - Go to Step 40  Go to Engine Cranks but Does Not Run 
40
  1. Clear the DTC with a scan tool.
  2. Operate the vehicle for 5 minutes.

    Does a DTC set during this ignition cycle?

 - Go to Diagnostic Trouble Code (DTC) List - Vehicle in Vehicle DTC Information System OK
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