What Does U1026 Mean?
The control module is not receiving valid engine RPM data over the SCP network. This prevents systems dependent on engine speed information from operating correctly.
Common Causes
35%
PCM failing to transmit RPM data on network bus
30%
Faulty crankshaft position sensor or camshaft sensor preventing RPM calculation
20%
Damaged network wiring between PCM and other modules
15%
Poor PCM ground connections affecting communication output
Diagnostic Steps
1
Step 1: Verify engine RPM is being calculated correctly by PCM using scan tool live data
2
Step 2: Check for engine performance codes related to crankshaft or camshaft position sensors
3
Step 3: Monitor RPM signal stability during cranking and running conditions
4
Step 4: Test PCM power, ground, and network connections for integrity
5
Step 5: Verify other modules can communicate with PCM to isolate if issue is transmit or receive problem
Estimated Repair Cost
$100 - $900
Parts + labor, varies by vehicle and location
The control module is not receiving valid engine RPM data over the SCP network. This prevents systems dependent on engine speed information from operating correctly.
The most common cause of U1026 (SCP (J1850) Invalid or Missing Data for Engine RPM) is: PCM failing to transmit RPM data on network bus
Typical repair costs for U1026 range from $100 to $900, depending on the vehicle, location, and whether you do it yourself or go to a shop.
May affect transmission shift quality, speedometer operation, and cruise control function. Vehicle may enter limp mode if RPM data is critical for operation.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to U1026 to identify the root cause.
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Quick Info
Category
Network
System
Network Communication / Engine Management
Difficulty
Type
Manufacturer
Recommended Tools
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