What Does P1142 Mean?
This code indicates the ECM's calculated engine load has fallen below the expected lower limit during a cross-check validation. The ECM compares calculated load values from multiple sensors (MAF, MAP, TPS, RPM) and when the load calculation from one source disagrees significantly with another, this code sets. This typically points to a metering sensor providing inaccurate data that causes the load model to compute an unrealistically low value.
Common Causes
30%
MAF sensor reading higher than actual airflow, causing calculated load to appear low relative to other inputs
25%
Intake manifold pressure sensor (MAP) reading incorrectly
20%
Throttle position sensor calibration error or drift
15%
Significant vacuum leak causing discrepancy between expected and actual manifold pressure
10%
ECM software calibration issue or corrupted adaptive values
Diagnostic Steps
1
Compare MAF sensor readings, MAP sensor readings, and calculated load percentage simultaneously at various RPM levels to identify which sensor disagrees.
2
Check the MAF sensor output against known-good values for the engine displacement at idle and 2500 RPM.
3
Verify the MAP sensor reads approximately 29 inHg (or ambient barometric pressure) with key on engine off, and appropriate vacuum at idle.
4
Inspect for vacuum leaks that could cause a discrepancy between MAF-based and MAP-based load calculations.
5
Clear adaptive fuel trim values and perform a drive cycle to allow the ECM to relearn; monitor if the code returns.
Estimated Repair Cost
$100 - $500
Parts + labor, varies by vehicle and location
This code indicates the ECM's calculated engine load has fallen below the expected lower limit during a cross-check validation. The ECM compares calculated load values from multiple sensors (MAF, MAP, TPS, RPM) and when the load calculation from one source disagrees significantly with another, this ...
The most common cause of P1142 (Load Calculation Cross Check Lower Limit Exceeded) is: MAF sensor reading higher than actual airflow, causing calculated load to appear low relative to other inputs
Typical repair costs for P1142 range from $100 to $500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Incorrect load calculation can cause poor fuel metering, hesitation, and reduced engine performance. The engine may not respond appropriately to load demands, which could be problematic during passing or hill climbing.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1142 to identify the root cause.
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Quick Info
Category
Powertrain
System
Engine Management / Fuel System
Difficulty
Type
Manufacturer
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