Signal Circuit Inspection

Check CAN BUS resistance
1. Ignition "OFF".
2. Measure the resistance between terminals 41 and 42 of PCM harness connector (Test 1)
3. Disconnect PCM connector and ABS (or ESP) control module connector.
4. Measure the resistance between terminals 41 and 42 of PCM harness connector (Test 2)
  
  Fig 1: Measuring Resistance Between Terminals 41 And 42 Of PCM Harness Connector (Test 2)
  Courtesy of KIA MOTORS AMERICA, INC.
  
  Specification :
  
  PCM and ABS (or ESP) module connected: 60 ± 3Ω (Test 1)
  
  PCM and ABS (or ESP) module disconnected: 120 ± 3Ω (Test 2)
5. Is CAN BUS resistance within the specification?
  YES
  - Go to step 2.
  NO
  - Below 10Ω for both conditions (disconnected, connected): Repair short between CAN BUS lines and go to "VERIFICATION OF VEHICLE REPAIR ".
  - 120Ω for both conditions (disconnected, connected): Go to step 4.
  - Infinite Ω for both conditions (disconnected, connected): Repair open in CAN communication circuit.
Check short to ground in CAN BUS
1. Ignition "OFF"
2. Disconnect PCM and ABS (or ESP) control module connector.
3. Check continuity between terminal 41 of PCM harness connector and chassis ground. (CAN HIGH line)
4. Check continuity between terminal 42 of PCM harness connector and chassis ground. (CAN LOW line)
  
  Fig 2: Checking Continuity Between Terminal 42 Of PCM Harness Connector And Chassis Ground
  Courtesy of KIA MOTORS AMERICA, INC.
  
  Specification: Discontinuity (Infinite Ω)
5. Is the measured resistance within the specification?
  YES
  - Go to step 3.
  NO
  - Repair short to ground in circuit and go to "VERIFICATION OF VEHICLE REPAIR ".
Check short to battery in CAN BUS
1. Ignition "OFF"
2. Disconnect PCM and ABS (or ESP) control module connector.
3. Ignition "ON"
4. Check the voltage between terminal 41 of PCM harness connector and chassis ground. (CAN HIGH line)
5. Check the voltage between terminal 42 of PCM harness connector and chassis ground. (CAN LOW line)
  
  Fig 3: Checking Voltage Between Terminal 42 Of PCM Harness Connector And Chassis Ground
  Courtesy of KIA MOTORS AMERICA, INC.
  
  Specification: 0.0V-0.1V
6. Is the measured voltage within the specification?
  YES
  - Go to step 4.
  NO
  - Repair short to battery and go to "VERIFICATION OF VEHICLE REPAIR ".
Check CAN BUS continuity
1. Ignition "OFF"
2. Disconnect PCM and ABS (or ESP) control module connector.
3. Check continuity in CAN HIGH line.
  (CAN HIGH: PCM connector terminal 41, ABS connector terminal 26, ESP connector terminal 35)
4. Check continuity CAN LOW line.
  (CAN LOW: PCM connector terminal 42, ABS connector terminal 15, ESP connector terminal 14)
  
  Fig 4: Checking Continuity CAN Low Line
  Courtesy of KIA MOTORS AMERICA, INC.
  
  Specification: Continuity (below 1.0Ω)
5. Is the measured resistance within the specification?
  YES
  - Go to "COMPONENT INSPECTION ".
  NO
  - Repair open in CAN BUS line and go to "VERIFICATION OF VEHICLE REPAIR ".