P0827 code definition
The P0827 trouble code detects an electrical issue with the up and down shift switch circuit.
What the P0827 code means
The P0827 code is a generic OBD-II trouble code that notes an electrical problem with the upshift/downshift switch circuit, which contains the upshift/downshift switch, the mode actuator, and many electrical components. The upshift/downshift switch is used by the driver to control gears and shifting in an automatic transmission that has manual mode. When the powertrain control module (PCM) notes that the upshift/downshift switch circuit is producing an abnormal voltage or resistance signal, the P0827 trouble code will be detected.
What causes the P0827 code?
The P0827 trouble code is most frequently caused by damage to the upshift/downshift switch, which is located in the cabin of the vehicle, usually on the shifter, but sometimes on the steering wheel or column. This damage is usually the result of spilled liquids. Damaged electrical components (such as the wires and connectors) in the system can also trigger the P0827 code.
What are the symptoms of the P0827 code?
When the P0827 trouble code is detected, the check engine soon warning light will likely illuminate on the instrument cluster, though not always. It is common for the overdrive light to flash as well. As far as drivability is concerned, the manual mode in the automatic transmission will be disarmed, and the transmission may enter “limp-in” mode, which will impact the smoothness of the shifting.
How does a mechanic diagnose the P0827 code?
The P0827 code will be diagnosed using a standard OBD-II trouble code scanner. A professional technician will use the scanner to observe the freeze frame data, to gather information about the code. The mechanic will also check to see if additional trouble codes are present. If there are multiple codes, then they should be addressed in the order in which they appear on the scanner. The mechanic will then reset the trouble codes, restart the vehicle, and check to see if the code remains detected. If it does not, then the code was likely triggered erroneously, or represents an intermittent issue.
If the P0827 trouble code remains detected, then the mechanic should undergo a visual inspection of the electronical components in the automatic transmission. Any open or shorted wires, or damaged or corroded connectors should be replaced (it is also common for the entire electrical harness to be replaced). Next, the upshift/downshift switch will need to be carefully inspected, and quite likely replaced.
If the problem has not been found, the reference voltage and ground signals should be checked, and a digital volt/ohmmeter can be used to test for resistance and continuity between all the circuits.
After any component is replaced, the mechanic will reset the trouble codes, restart the vehicle, and once again check to see if the codes return. By doing this, the technician will be able to identify as soon as the issue has been resolved.
Common mistakes when diagnosing the P0827 code
The mistake that is made most often when diagnosing the P0827 code is the failure to properly comply with the OBD-II trouble code diagnosis protocol. Technicians should abide by the protocol step by step, at all times, to guarantee that every repair is both thorough and efficient.
It is fairly common for damaged switches to go unnoticed, because liquid spills do not always leave physical signs of damage.
How serious is the P0827 code?
A vehicle with a detected P0827 trouble code will still be drivable, though the manual shift mode may be deactivated, and shifting may be a little harsh. If this code is not resolved, further damage can occur to the transmission, so the P0827 code should be addressed as soon as it is detected.
What repairs can fix the P0827 code?
The most common repairs for the P0827 code are a replacement of the upshift/downshift switch, and replacement of the electrical components. In very rare cases, the PCM may need to be replaced.
Additional comments for consideration regarding the P0827 code
The P0827 trouble code only applies to vehicles that have automatic transmissions with manual shift mode.
Need help with a P0827 code?
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This article originally appeared on YourMechanic.com as P0827 OBD-II Trouble Code: Up and Down Shift Switch Input Circuit Low and was authored by Brady Klopfer.