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Home / DTC / U1116 — Lost Communication With Motor Electronics Coolant Pump (C-CAN)

U1116 — Lost Communication With Motor Electronics Coolant Pump (C-CAN)

Detailed page for trouble code U1116.

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U1116

HYUNDAI U — Network/User

Lost Communication With Motor Electronics Coolant Pump (C-CAN)

Brand: HYUNDAI
Type: U — Network/User
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Open or short in CAN H/L wiring to the coolant pump module
  • Corroded/loose connector at the coolant pump or junction box
  • Faulty coolant pump motor electronics / module
  • Blown fuse or lost supply/ground to the pump module
  • CAN bus short to chassis or battery voltage (CAN H or CAN L shorted)
  • Missing or failed CAN termination resistor(s)

Symptoms

  • Malfunction indicator lamp (MIL) or message and U1116 stored in memory
  • Coolant pump not operating when expected or running in limp/default mode
  • Reduced cooling performance or overheating under some conditions
  • Related modules reporting multiple CAN comm errors or network faults
  • No CAN frames received from pump node when scanned with a diagnostic tool

What to check

  • Retrieve freeze frame and network scan results with a capable scan tool
  • Visual inspection of coolant pump connector and harness for corrosion, damage, or water intrusion
  • Verify fuses/relays supplying the pump and related junction box are intact
  • Check battery voltage and charging system for adequate voltage (11–14.5 V expected)
  • Inspect for diagnostic trouble codes in other CAN modules that indicate a bus issue
  • Confirm ground continuity for the pump module to chassis

Signal parameters

  • CAN High (idle): ~2.5 V (oscillating around this value when network active)
  • CAN Low (idle): ~2.5 V (oscillating inversely to CAN High)
  • CAN differential: dominant pulses typically ~1.0–2.0 V differential during transmission
  • Bus idle differential ~0 V (small noise), bus resistance ≈ 60 Ω with two 120 Ω terminators
  • Module supply to pump: approx. battery voltage (11–14.5 V) when key On
  • Expected CAN message periodicity: nodes commonly transmit periodic status frames (tens to hundreds of ms). Absence of expected periodic frames from the pump node indicates lost comms.

Diagnostic algorithm

  1. Use a network scan tool to confirm U1116 and check for other U-codes or module absences on C‑CAN.
  2. Record conditions when the code set (key on/off, engine running, temperatures). Try clearing the code and see if it returns and under what conditions.
  3. Visually inspect the coolant pump connector and harness for corrosion, bent pins, damage, or water entry. Repair any obvious issues.
  4. Verify power and ground at the pump connector with key ON: battery voltage at supply pin and good ground continuity. Repair supply/ground faults before proceeding.
  5. Check related fuses and relays in the junction box that feed the pump module; replace if open.
  6. Backprobe or access the CAN H and CAN L at the pump connector or nearest junction. With an oscilloscope check for proper CAN waveforms and differential activity while key ON and during cranking.
  7. Measure resistance between CAN H and CAN L with ignition off — expect ≈ 60 Ω. If open or very high/low, isolate by disconnecting segments or modules to locate the fault.
  8. Disconnect the coolant pump module and observe if the rest of the bus recovers (other modules communication restored). If disconnecting the pump clears other network errors, suspect pump module or its wiring as the fault.
  9. If wiring and supply/ground are good but no communication from the pump, consider replacing or reprogramming the pump motor electronics per manufacturer procedures.
  10. After repairs, clear codes and perform a functional test and network scan to confirm the U1116 does not return and that the pump responds to commands.

Likely causes

  • Damaged connector or wiring at the coolant pump (most common on routed harnesses)
  • Loss of module supply power or ground at the pump
  • Failed pump motor electronics (module internal fault)
  • Shorted CAN pair or high resistance on the CAN bus
  • Failed termination resistor or other module pulling the bus down

Fault status

⚠️ Status
Lost communication with Motor Electronics Coolant Pump (C‑CAN). CAN messages from the coolant pump module are not being received. Inspect wiring, power/ground, connectors, and CAN bus integrity.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-2.5 hours

Similar codes

U0100 U0073 U0121 U1100 U1117
371

Browse 371 HYUNDAI manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

HYUNDAI

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Code

U1116

MITSUBISHI U — Network/User

KOS CAN timeout/Not equipped

Brand: MITSUBISHI
Type: U — Network/User
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Open or short in CAN H/L wiring to the coolant pump module
  • Corroded/loose connector at the coolant pump or junction box
  • Faulty coolant pump motor electronics / module
  • Blown fuse or lost supply/ground to the pump module
  • CAN bus short to chassis or battery voltage (CAN H or CAN L shorted)
  • Missing or failed CAN termination resistor(s)

Symptoms

  • Malfunction indicator lamp (MIL) or message and U1116 stored in memory
  • Coolant pump not operating when expected or running in limp/default mode
  • Reduced cooling performance or overheating under some conditions
  • Related modules reporting multiple CAN comm errors or network faults
  • No CAN frames received from pump node when scanned with a diagnostic tool

What to check

  • Retrieve freeze frame and network scan results with a capable scan tool
  • Visual inspection of coolant pump connector and harness for corrosion, damage, or water intrusion
  • Verify fuses/relays supplying the pump and related junction box are intact
  • Check battery voltage and charging system for adequate voltage (11–14.5 V expected)
  • Inspect for diagnostic trouble codes in other CAN modules that indicate a bus issue
  • Confirm ground continuity for the pump module to chassis

Signal parameters

  • CAN High (idle): ~2.5 V (oscillating around this value when network active)
  • CAN Low (idle): ~2.5 V (oscillating inversely to CAN High)
  • CAN differential: dominant pulses typically ~1.0–2.0 V differential during transmission
  • Bus idle differential ~0 V (small noise), bus resistance ≈ 60 Ω with two 120 Ω terminators
  • Module supply to pump: approx. battery voltage (11–14.5 V) when key On
  • Expected CAN message periodicity: nodes commonly transmit periodic status frames (tens to hundreds of ms). Absence of expected periodic frames from the pump node indicates lost comms.

Diagnostic algorithm

  1. Use a network scan tool to confirm U1116 and check for other U-codes or module absences on C‑CAN.
  2. Record conditions when the code set (key on/off, engine running, temperatures). Try clearing the code and see if it returns and under what conditions.
  3. Visually inspect the coolant pump connector and harness for corrosion, bent pins, damage, or water entry. Repair any obvious issues.
  4. Verify power and ground at the pump connector with key ON: battery voltage at supply pin and good ground continuity. Repair supply/ground faults before proceeding.
  5. Check related fuses and relays in the junction box that feed the pump module; replace if open.
  6. Backprobe or access the CAN H and CAN L at the pump connector or nearest junction. With an oscilloscope check for proper CAN waveforms and differential activity while key ON and during cranking.
  7. Measure resistance between CAN H and CAN L with ignition off — expect ≈ 60 Ω. If open or very high/low, isolate by disconnecting segments or modules to locate the fault.
  8. Disconnect the coolant pump module and observe if the rest of the bus recovers (other modules communication restored). If disconnecting the pump clears other network errors, suspect pump module or its wiring as the fault.
  9. If wiring and supply/ground are good but no communication from the pump, consider replacing or reprogramming the pump motor electronics per manufacturer procedures.
  10. After repairs, clear codes and perform a functional test and network scan to confirm the U1116 does not return and that the pump responds to commands.

Likely causes

  • Damaged connector or wiring at the coolant pump (most common on routed harnesses)
  • Loss of module supply power or ground at the pump
  • Failed pump motor electronics (module internal fault)
  • Shorted CAN pair or high resistance on the CAN bus
  • Failed termination resistor or other module pulling the bus down

Fault status

⚠️ Status
Lost communication with Motor Electronics Coolant Pump (C‑CAN). CAN messages from the coolant pump module are not being received. Inspect wiring, power/ground, connectors, and CAN bus integrity.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-2.5 hours

Similar codes

U0100 U0073 U0121 U1100 U1117
406

Browse 406 MITSUBISHI manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

MITSUBISHI

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+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email
Code

U1116

Other U — Network/User

SCP (J1850) Invalid or Missing Data for Electrical Energy Management

Brand: Other
Type: U — Network/User
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Open or short in CAN H/L wiring to the coolant pump module
  • Corroded/loose connector at the coolant pump or junction box
  • Faulty coolant pump motor electronics / module
  • Blown fuse or lost supply/ground to the pump module
  • CAN bus short to chassis or battery voltage (CAN H or CAN L shorted)
  • Missing or failed CAN termination resistor(s)

Symptoms

  • Malfunction indicator lamp (MIL) or message and U1116 stored in memory
  • Coolant pump not operating when expected or running in limp/default mode
  • Reduced cooling performance or overheating under some conditions
  • Related modules reporting multiple CAN comm errors or network faults
  • No CAN frames received from pump node when scanned with a diagnostic tool

What to check

  • Retrieve freeze frame and network scan results with a capable scan tool
  • Visual inspection of coolant pump connector and harness for corrosion, damage, or water intrusion
  • Verify fuses/relays supplying the pump and related junction box are intact
  • Check battery voltage and charging system for adequate voltage (11–14.5 V expected)
  • Inspect for diagnostic trouble codes in other CAN modules that indicate a bus issue
  • Confirm ground continuity for the pump module to chassis

Signal parameters

  • CAN High (idle): ~2.5 V (oscillating around this value when network active)
  • CAN Low (idle): ~2.5 V (oscillating inversely to CAN High)
  • CAN differential: dominant pulses typically ~1.0–2.0 V differential during transmission
  • Bus idle differential ~0 V (small noise), bus resistance ≈ 60 Ω with two 120 Ω terminators
  • Module supply to pump: approx. battery voltage (11–14.5 V) when key On
  • Expected CAN message periodicity: nodes commonly transmit periodic status frames (tens to hundreds of ms). Absence of expected periodic frames from the pump node indicates lost comms.

Diagnostic algorithm

  1. Use a network scan tool to confirm U1116 and check for other U-codes or module absences on C‑CAN.
  2. Record conditions when the code set (key on/off, engine running, temperatures). Try clearing the code and see if it returns and under what conditions.
  3. Visually inspect the coolant pump connector and harness for corrosion, bent pins, damage, or water entry. Repair any obvious issues.
  4. Verify power and ground at the pump connector with key ON: battery voltage at supply pin and good ground continuity. Repair supply/ground faults before proceeding.
  5. Check related fuses and relays in the junction box that feed the pump module; replace if open.
  6. Backprobe or access the CAN H and CAN L at the pump connector or nearest junction. With an oscilloscope check for proper CAN waveforms and differential activity while key ON and during cranking.
  7. Measure resistance between CAN H and CAN L with ignition off — expect ≈ 60 Ω. If open or very high/low, isolate by disconnecting segments or modules to locate the fault.
  8. Disconnect the coolant pump module and observe if the rest of the bus recovers (other modules communication restored). If disconnecting the pump clears other network errors, suspect pump module or its wiring as the fault.
  9. If wiring and supply/ground are good but no communication from the pump, consider replacing or reprogramming the pump motor electronics per manufacturer procedures.
  10. After repairs, clear codes and perform a functional test and network scan to confirm the U1116 does not return and that the pump responds to commands.

Likely causes

  • Damaged connector or wiring at the coolant pump (most common on routed harnesses)
  • Loss of module supply power or ground at the pump
  • Failed pump motor electronics (module internal fault)
  • Shorted CAN pair or high resistance on the CAN bus
  • Failed termination resistor or other module pulling the bus down

Fault status

⚠️ Status
Lost communication with Motor Electronics Coolant Pump (C‑CAN). CAN messages from the coolant pump module are not being received. Inspect wiring, power/ground, connectors, and CAN bus integrity.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0-2.5 hours

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