Code
U1719
ALFA ROMEO
U — Network/User
CAN bus communication between engine control module and electric drive
Views:
UK: 6
EN: 7
RU: 9
AI status
Completed
Completed
100%
Causes
- Damaged or corroded CAN wiring or connectors between ECM and electric drive
- Loose, bent or corroded connector pins at either module
- Open or shorted CAN_H or CAN_L conductors (to battery or ground)
- Missing or incorrect network termination (open/shorted resistors)
- Failed CAN transceiver in the ECM or electric drive module
- Intermittent power or ground to one of the modules (fuse, relay, ground strap)
Symptoms
- Malfunction Indicator Lamp (MIL) or warning lamp illuminated
- Messages or warnings about electric drive, reduced power or limp mode
- Loss of electric drive control or occasional loss of drive assist
- Intermittent or constant fault codes stored in multiple modules
- Possible inability to communicate with the electric drive module with a scan tool
What to check
- Read DTCs with a capable scan tool and capture freeze-frame and history data
- Check for related U-codes on other modules (BIU, ABS, TCM) to identify affected network
- Visually inspect connectors, terminals and wiring for corrosion, damage or water ingress
- Verify battery voltage and perform a quick check of main fuses and relays for the electric drive circuit
- With ignition on, measure CAN_H and CAN_L voltages at ECM and electric drive connector pins
- Check termination resistance (with power off) across CAN_H and CAN_L — should be ~60 ohms for a properly terminated two-node segment
Signal parameters
- Idle voltages (typical): CAN_H ≈ 2.5 V, CAN_L ≈ 2.5 V (each referenced to chassis ground)
- Dominant state typical: CAN_H ≈ 3.5 V, CAN_L ≈ 1.5 V (differential ≈ 2.0 V)
- Termination resistance (power off): ≈ 60 ohms between CAN_H and CAN_L (two 120 Ω terminators in parallel)
- Common bus speeds: 250 kb/s or 500 kb/s (verify vehicle-specific)
- Fault conditions to watch for: stuck-high/low, excessive noise, missing dominant pulses, abnormal rise/fall times
Diagnostic algorithm
- Connect a qualified scan tool; record U1719 and any other DTCs, freeze frame and occurrence count.
- Identify which CAN network (powertrain CAN, dedicated electric drive CAN) is affected and which modules share it.
- Visually inspect connectors, pins and harness routing between ECM and electric drive module for damage, corrosion, or water intrusion. Repair as needed.
- Verify vehicle battery voltage (key on engine off) and check fuses/relays that supply the electric drive and ECM.
- With ignition on, measure DC voltages on CAN_H and CAN_L at both the ECM and electric drive module connectors; confirm idle voltages ~2.5 V and compare sides.
- With power off, measure termination resistance between CAN_H and CAN_L at convenient access points; expect ≈60 Ω. If out of range, trace missing/bad terminators.
- Use an oscilloscope or CAN bus analyzer to view waveforms while attempting communication; look for missing frames, dominant timeouts, excessive noise or abnormal edges.
- Perform a wiggle test on wiring and connectors while monitoring the network to duplicate intermittent faults; repair any failure points found.
- If wiring and termination check good, isolate modules by disconnecting them one at a time (where safe and manufacturer-approved) to identify a module causing bus errors (observe bus off conditions).
- If a module is suspected, verify module power/ground and update or reflash software per manufacturer TSBs; replace module only after confirming hardware fault.
- Clear codes, re-test under the same conditions and perform a road test to confirm repair. Document intermittent occurrences and perform extended monitoring if necessary.
Likely causes
- Loose or corroded connector at the electric drive module or ECM
- Broken CAN_H or CAN_L wire (chafing, pinched harness)
- Failed CAN transceiver on ECM or electric drive module
- Failed or missing termination resistor(s) on the CAN segment
- Faulty power/ground to the electric drive module (blown fuse, poor ground)
Fault status
Status
U1719 — CAN communication fault detected between Engine Control Module and Electric Drive (lost or corrupted messages).
Repair difficulty: Medium
Diagnostic time: 1.0-3.0 hours
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Code
U1719
FIAT
U — Network/User
CAN bus communication between engine control module and electric drive
Views:
UK: 4
EN: 3
RU: 6
AI status
Completed
Completed
100%
Causes
- Damaged or corroded CAN wiring or connectors between ECM and electric drive
- Loose, bent or corroded connector pins at either module
- Open or shorted CAN_H or CAN_L conductors (to battery or ground)
- Missing or incorrect network termination (open/shorted resistors)
- Failed CAN transceiver in the ECM or electric drive module
- Intermittent power or ground to one of the modules (fuse, relay, ground strap)
Symptoms
- Malfunction Indicator Lamp (MIL) or warning lamp illuminated
- Messages or warnings about electric drive, reduced power or limp mode
- Loss of electric drive control or occasional loss of drive assist
- Intermittent or constant fault codes stored in multiple modules
- Possible inability to communicate with the electric drive module with a scan tool
What to check
- Read DTCs with a capable scan tool and capture freeze-frame and history data
- Check for related U-codes on other modules (BIU, ABS, TCM) to identify affected network
- Visually inspect connectors, terminals and wiring for corrosion, damage or water ingress
- Verify battery voltage and perform a quick check of main fuses and relays for the electric drive circuit
- With ignition on, measure CAN_H and CAN_L voltages at ECM and electric drive connector pins
- Check termination resistance (with power off) across CAN_H and CAN_L — should be ~60 ohms for a properly terminated two-node segment
Signal parameters
- Idle voltages (typical): CAN_H ≈ 2.5 V, CAN_L ≈ 2.5 V (each referenced to chassis ground)
- Dominant state typical: CAN_H ≈ 3.5 V, CAN_L ≈ 1.5 V (differential ≈ 2.0 V)
- Termination resistance (power off): ≈ 60 ohms between CAN_H and CAN_L (two 120 Ω terminators in parallel)
- Common bus speeds: 250 kb/s or 500 kb/s (verify vehicle-specific)
- Fault conditions to watch for: stuck-high/low, excessive noise, missing dominant pulses, abnormal rise/fall times
Diagnostic algorithm
- Connect a qualified scan tool; record U1719 and any other DTCs, freeze frame and occurrence count.
- Identify which CAN network (powertrain CAN, dedicated electric drive CAN) is affected and which modules share it.
- Visually inspect connectors, pins and harness routing between ECM and electric drive module for damage, corrosion, or water intrusion. Repair as needed.
- Verify vehicle battery voltage (key on engine off) and check fuses/relays that supply the electric drive and ECM.
- With ignition on, measure DC voltages on CAN_H and CAN_L at both the ECM and electric drive module connectors; confirm idle voltages ~2.5 V and compare sides.
- With power off, measure termination resistance between CAN_H and CAN_L at convenient access points; expect ≈60 Ω. If out of range, trace missing/bad terminators.
- Use an oscilloscope or CAN bus analyzer to view waveforms while attempting communication; look for missing frames, dominant timeouts, excessive noise or abnormal edges.
- Perform a wiggle test on wiring and connectors while monitoring the network to duplicate intermittent faults; repair any failure points found.
- If wiring and termination check good, isolate modules by disconnecting them one at a time (where safe and manufacturer-approved) to identify a module causing bus errors (observe bus off conditions).
- If a module is suspected, verify module power/ground and update or reflash software per manufacturer TSBs; replace module only after confirming hardware fault.
- Clear codes, re-test under the same conditions and perform a road test to confirm repair. Document intermittent occurrences and perform extended monitoring if necessary.
Likely causes
- Loose or corroded connector at the electric drive module or ECM
- Broken CAN_H or CAN_L wire (chafing, pinched harness)
- Failed CAN transceiver on ECM or electric drive module
- Failed or missing termination resistor(s) on the CAN segment
- Faulty power/ground to the electric drive module (blown fuse, poor ground)
Fault status
Status
U1719 — CAN communication fault detected between Engine Control Module and Electric Drive (lost or corrupted messages).
Repair difficulty: Medium
Diagnostic time: 1.0-3.0 hours
Similar codes
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
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👍 Like
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