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Home >> Chevrolet >> 2018 >> Spark LT, Automatic CVT Trans >> Repair and Diagnosis >> External Pages >> Different car >> Section 56 (Automatic Transmission - JATCO CVT) >> Diagnostic Information and Procedures >> DTC P0705, P0706 or P0851: Transmission Range Switch (MR8) >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2017 Chevrolet Spark. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition/Vehicle & All vehicle systems - Off
  2. Disconnect the electrical connector: B15 Transmission Internal Mode Switch
    NOTE: It may take up to 2 min for all vehicle systems to power down before an accurate ground or low reference circuit continuity test can be performed.
  3. Ignition On - Engine Off
  4. Verify a test lamp turns On between the test points: Ground circuit terminal 1 & Battery Positive Cable
    • If the test lamp does not turn On 
    1. Ignition/Vehicle - Off & Remove - Test lamp
    2. Test for less than 35 Ω between the test points: Ground circuit terminal 1 @ Component harness & Chassis Ground
      • If 35 Ω or greater - Repair the open/high resistance in the circuit.
      • If less than 35 Ω
    3. Test for infinite resistance between the test points: Ground circuit terminal 1 & and all other terminals of the B15 Transmission Internal Mode Switch Harness Connector
      • If less than infinite resistance - Repair the short between the circuits.
      • If infinite resistance
    • If the test lamp turns On 
  5. Test for greater than B+ (-1.0) V between the test points: Signal circuit terminal 4 & Ground circuit terminal 1 or Chassis Ground
    NOTE: The Transmission Control Module provides a low current voltage on the signal circuit.
    • If less than B+ (-1.0) V 
    1. Ignition Off
    2. Disconnect the electrical connector: X1 @ K71 Transmission Control Module
    3. Test for less than 2 Ω between the test points: Signal circuit terminal 4 @ Component harness & Terminal 3 X1 @ Control module harness
      • If 2 Ω or greater - Repair the open/high resistance in the circuit.
      • If less than 2 Ω
    4. Test for infinite resistance between the test points: Signal circuit terminal 4 & Ground circuit terminal 1 or Chassis Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • If infinite resistance
    5. Test for infinite resistance between the test points: Signal circuit terminal 4 & and all other terminals of the B15 Transmission Internal Mode Switch Harness Connector
      • If less than infinite resistance - Repair the short between the circuits.
      • If infinite resistance - Replace the component: K20 Engine Control Module
    • If B+ (-1.0) V or greater 
  6. Test for greater than B+ (-1.0) V between the test points: Ignition circuit terminal 7 & Chassis Ground
    • If less than B+ (-1.0) V 
    1. Ignition Off
    2. Test for less than 2 Ω between the test points: Ignition circuit terminal 7 & Output terminal @ F06AU Fuse-X50A Fuse Block - Underhood
      • If 2 Ω or greater - Repair the open/high resistance in the circuit.
      • If less than 2 Ω - Verify the fuse is OK and there is voltage at the fuse.
      • If in the specified range 
    1. Ignition Off
    2. Test for infinite resistance between the test points: Ignition circuit terminal 7 & Chassis Ground
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • If infinite resistance
    3. Remove the component: KR157 Transmission Control Module Relay
    4. Test for infinite resistance between the test points: Ignition circuit terminal 7 & and all other terminals of the B15 Transmission Internal Mode Switch Harness Connector
      • If less than infinite resistance - Repair the short between the circuits.
      • If infinite resistance - Verify the fuse is OK and there is voltage at the fuse.
    • If B+ (1.0) V or greater 
  7. Test for 0.01 to 0.25 V between the test points:
    NOTE: The Transmission Control Module provides a low current voltage on the following circuits.
    • Signal circuit terminal 5 & Chassis Ground
    • Signal circuit terminal 9 & Chassis Ground
    • Signal circuit terminal 2 & Chassis Ground
    • Signal circuit terminal 3 & Chassis Ground
    • Signal circuit terminal 6 & Chassis Ground
    • If less than 0.01 V 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: K71 Transmission Control Module X2.
    3. Test for less than 2 Ω in the affected signal circuit end to end.
      • Signal circuit terminal 5 @ Component harness & Terminal 20 X2 @ Control module harness
      • Signal circuit terminal 9 @ Component harness & Terminal 19 X2 @ Control module harness
      • Signal circuit terminal 2 @ Component harness & Terminal 9 X2 @ Control module harness
      • Signal circuit terminal 3 @ Component harness & Terminal 7 X2 @ Control module harness
      • Signal circuit terminal 6 @ Component harness & Terminal 18 X2 @ Control module harness
      • If 2 Ω or greater - Repair the open/high resistance in the circuit.
      • If less than 2 Ω
    4. Test for infinite resistance between the affected signal circuit and chassis ground.
      • If less than infinite resistance - Repair the short to ground on the circuit.
      • If infinite resistance
    5. Test for infinite resistance between the test points: The affected signal circuit & and all other terminals of the B15 Transmission Internal Mode Switch Harness Connector
      • If less than infinite resistance, repair the shorted together condition in the affected circuits.
      • If infinite resistance - Replace the component: B15 Transmission Internal Mode Switch.
    • If greater than 0.25 V 
    1. Ignition/Vehicle - Off
    2. Disconnect the electrical connector: K71 Transmission Control Module X2.
    3. Test for infinite resistance between the test points: The affected signal circuit & and all other terminals of the B15 Transmission Internal Mode Switch Harness Connector.
      • If less than infinite resistance, repair the shorted together condition in the affected circuits.
      • If infinite resistance - Replace the component: K71 Transmission Control Module.
    • If between 0.01 and 0.25 V 
  8. Replace the: B15 Transmission Internal Mode Switch.
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