U1026 - SCP Invalid or Missing Data for Engine RPM

Repair Importance Level: 3/3
Repair Difficulty Level: 3/3   
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U1026 Possible Causes

  • Faulty / intermittent ignition switch connections
  • J1850 / SCP Bus wiring intermittently open, shorted to power or ground
  • Faulty / intermittent connection at the Powertrain Control Module (PCM)
  • Faulty / intermittent connection at the Instrument Panel Cluster (IPC)
  • Faulty / intermittent connection at the Transfer Case Control Module (TCCM)

First diagnose U1026 code

    Check the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded terminals.

U1026 Tech Notes

This is typically an electrical wiring connection issue at one of the controllers being monitored by the manufacturer.
It can occur if:
Someone changes a battery while the ignition switch is left on, that is, left in the “Run” position.
Someone flashes/upgrades their engine controller – other modules unable to communicate with PCM during this process – this will set U1026 at a multitude of controllers on the vehicle – all false codes. Erase and carry on.
May need to disconnect both battery cables and touch them together for 15 seconds. Reattach battery cables, positive first, then negative and see if a soft reset helps.

Cost of diagnosing the U1026 code

    Labor: 1.0

    The cost of diagnosing the U1026 code is 1.0 hour of labor. The auto repair labor rates vary by location, your vehicle's make and model, and even your engine type. Most auto repairs shops charge between $75 and $150 per hour.

When is the U1026 code detected?

When the PCM is unable to communicate with any other controller on the bus network at any time while the ignition switch is in the “Run” position.

U1026 Possible Symptoms

  • Engine Light ON (or Service Engine Soon Warning Light)
  • Service 4WD Light ON
  • Engine cranks but may not start – may be intermittent
  • May / may not shift from 2-wheel drive to 4-wheel drive / 4-wheel drive to 2-wheel drive
  • May or may not be able to communicate with a scan tool / depends on problem

U1026 Description

This is a manufacturer specific fault code and can be used for several different faults, depending upon what the manufacturer wants to use it for. The Powertrain Control Module (PCM) communicates over the Serial Communication Protocol (SCP) bus network, or J1850 bus. This is a medium-speed bus communication system and is fault tolerant, which means any type of intermittent/loose connection at these controllers will cause this code to set in memory, but will still operate, provided a data path is available. When the PCM is unable to communicate with any other controller at any time while the ignition switch is turned on, code U1026 will set. This is the typical reason for this code to set.
OBDII Code U1026 - SCP Invalid or Missing Data for Engine RPM - AutoCodes.com

U1026 More Information

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U1026 Information for specific makes

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U1026 Comments

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