What Does P1595 Mean?
This code indicates the automatic transmission diagnosis input signal circuit is reading a voltage that is lower than the expected minimum threshold. This is the low-input variant, suggesting a short to ground, failed sensor with low output, or a wiring issue pulling the signal voltage down. The PCM cannot properly interpret the transmission's operating state.
Common Causes
30%
Short to ground in the transmission input signal wiring
25%
Failed internal transmission sensor with low output
20%
Corroded or water-damaged transmission connector creating a ground path
15%
Chafed wiring harness contacting the transmission case
10%
Contaminated ATF causing sensor malfunction
Diagnostic Steps
1
Monitor the transmission diagnosis input signal on live data; confirm it reads below the expected minimum value.
2
Disconnect the transmission connector and check if the signal voltage at the PCM rises—if so, the fault is at the transmission or its internal wiring.
3
Inspect the external transmission wiring harness for chafing, especially where it contacts metal surfaces or crosses near heat sources.
4
Check the transmission connector for fluid contamination, corrosion, or water intrusion.
5
If the fault is internal to the transmission, further diagnosis may require valve body or internal harness inspection.
Estimated Repair Cost
$150 - $900
Parts + labor, varies by vehicle and location
This code indicates the automatic transmission diagnosis input signal circuit is reading a voltage that is lower than the expected minimum threshold. This is the low-input variant, suggesting a short to ground, failed sensor with low output, or a wiring issue pulling the signal voltage down. The PCM...
The most common cause of P1595 (Automatic transmission diagnosis input signal circuit low input) is: Short to ground in the transmission input signal wiring
Typical repair costs for P1595 range from $150 to $900, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Transmission may enter limp mode with only one gear available, severely limiting vehicle performance. Unexpected shift behavior could occur in traffic if the fault is intermittent.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1595 to identify the root cause.
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Quick Info
Category
Powertrain
System
Automatic Transmission
Difficulty
Type
Manufacturer
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