U1008

Code

Other U — Network/User

SCP (J1850) Invalid or Missing Data for Engine Torque

Brand: Other

Type: U — Network/User

Views: UK: 31 EN: 88 RU: 92

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Loss of or intermittent J1850/SCP network communication
Faulty or disconnected engine control module (ECM/PCM) or other sender module
Damaged, corroded or shorted network wiring, connectors or grounds
Module software mismatch or corrupted calibration
Faulty network transceiver or missing/incorrect network termination
Invalid engine torque calculation from the sending module (sensor input fault or internal fault)

Symptoms

MIL (Check Engine) lamp or network-related dash warning
Reduced engine or transmission performance / limp-home behavior (if torque input to TCM is lost)
Inaccurate or frozen torque-related gauges or readings
Other network modules reporting related U-codes or communication faults

What to check

Scan vehicle and record U1008 plus any additional U- or P-codes and freeze frame data
Use a scan tool to watch live engine torque PID and verify presence, validity and update rate
Inspect connectors and wiring for corrosion, pin damage, proper mating and secure grounds at ECM/PCM and junction points
Check vehicle battery voltage and main ground connections while monitoring the bus for voltage drops
Look for other modules that report lost communication (compare reported torque on other modules if available)
If available, capture the J1850/SCP bus waveform with an oscilloscope to look for noise, missing frames or distortion

Signal parameters

Parameter: calculated engine torque (sender: ECM/PCM or designated torque-calculation module)
Data type: scaled byte/word (signed or unsigned) as defined by OEM; units commonly Nm or % torque
Expected update behavior: periodic message from sender (typical periodic rate varies by vehicle — verify OEM spec)
Valid value check: should be within OEM-specified range; reserved/invalid indicator bytes (e.g., 0xFF/0xFFFF) indicate invalid data
Message integrity: includes expected message ID and correct length; corrupted/short messages indicate bus or transceiver faults

Diagnostic algorithm

Record all stored and pending codes. Note freeze frame data and operational conditions when U1008 set.
With a capable scan tool, monitor the engine torque PID. Confirm whether the PID is present, updating, and within a plausible range.
Check for other network-related U-codes. If multiple modules report communications issues, suspect bus wiring, power or ground.
Visually inspect ECM/PCM and related module connectors and harnesses for corrosion, water intrusion, damaged pins, or loose terminals.
Verify battery voltage (key on and cranking) and check primary ground integrity. Repair any poor battery/ground connections.
Perform a wiggle test on wiring harnesses while monitoring the torque PID for intermittent loss. Repair or replace damaged harness sections.
If wiring and power/ground are good, check the J1850/SCP bus for correct signaling with an oscilloscope or specialized bus tester; look for missing frames, noise, or improper voltage levels.
If bus and wiring check out, review OEM technical service information for module calibration or software updates. Reflash or reprogram modules only per OEM procedure.
If problem persists and the sending module is isolated as faulty, replace the module per service instructions and verify repair by clearing codes and performing verification drive.
After repair, confirm no related codes return and that torque PID updates correctly under all operating conditions.

Likely causes

Bad connector or wiring at the ECM/PCM or at an intermediate junction
ECM/PCM not transmitting torque message due to internal fault or reflash requirement
Intermittent bus voltage or poor ground causing corrupted packets
Network transceiver failure on the sending or receiving module

Fault status

⚠️ Status

SCP (J1850) invalid or missing Engine Torque data. Indicates the torque message is absent or contains an invalid value or checksum; communication or sender integrity issue.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-3.0 hours