P0828 code definition
The P0828 code is a generic powertrain code related to the transmission, including pressure faults and sensor failures. In this case, the engine control module (ECM) has found a fault with the input circuit for the up and down switch, reading higher than allowed preset parameters.
Codes related to the P0828 include:
- P0819: Up and Down Shift to Transmission Range Correlation
- P0826: Up and Down Shift Switch Circuit
- P0827: Up and Down Shift Circuit Low
What the P0828 code means
If the ECM detects an abnormality in the voltage or resistance signal in the Up and Down Shift Switch circuit between the switch and the transmission range correlation unit a P0828 code will be stored. The circuit includes the switch, all system wiring and connectors, as well as the mode actuators. You can locate the Up and Down Shift Switch near the shifter in the passenger compartment of the vehicle, which may be mounted on the steering wheel (such as “paddle shifters”. These switches are only used on vehicles with manually shiftable automatic transmissions (automated manuals).
Vehicles equipped with an OBD-II system use a computerized control system to use various inputs to calculate engine driveability inputs to determine the gear ration needed to achieve the best fuel efficiency, engine performance, and vehicle life.
The ECM will initiate up and down shifting through shift solenoids in order to actuate fluid transfer between the hydraulic circuits in each set of gears, allowing the driver to choose between multiple shift strategies, such as “Normal” and “Performance” modes. A manually shiftable automatic transmission will allow a driver to up or down shift quickly through the use of a shift or button near the shift lever.
What causes the P0828 code?
Several problems may cause a P0828 code including:
- Damaged or defective up and down switch
- Damaged, corroded, or poor electrical connection with the up and down shift switch
- Open or shorted harness, wiring, or connectors for the up and down switch
- Liquids spilled on the shifter in the passenger compartment of the vehicle
- Damaged or defective ECM (rare)
What are the symptoms of the P0828 code?
Symptoms of a P0828 code may include:
- Check engine or warning light may illuminate
- There may be no symptoms for this diagnostic trouble code (DTC)
- The manual shifter function may be disabled
- The vehicle may go into “limp mode” - meaning the transmission may shift more roughly and the torque converter lock up mode may be eliminated
- The overdrive light may flash
How does a mechanic diagnose the P0828 code?
A mechanic may use several methods to diagnose a P0828 trouble code, including:
- Utilize an OBD-II scanner to check for a stored P0828 trouble code
- Visually inspect the passenger compartment for any spills that may have got into the Up and Down Shift Switch
- Visually inspect the circuits wiring for signs of damage, corrosion, or wear
- Check reference voltage and ground signals at the Up and Down Shift Switch and actuators
- Use digital volt/ohmmeter to check for continuity and resistance if reference voltage and/or ground signals were open
- Test all related circuits and switches for continuity and resistance
Common Mistakes when Diagnosing the P0828 Code
Before checking and diagnosing faulty transmission wiring, be sure to check whether liquid was spilled on the shifter in the passenger compartment. Clean and repair any damaged wiring or connectors at the shift switch location and retest the system before performing more complicated repairs.
How Serious is the P0828 code?
Because a vehicle’s safe driving operation may be impacted due to faults that store a P0828 code, this code is considered a potentially serious code. When this code appears, it is recommended to immediately take your vehicle to your local service center or mechanic for repair and diagnosis.
What repairs can fix the P0828 code?
Several repairs can fix a P0828 trouble code and include:
- Clean out the shifter area of any spilled liquids
- Repair or replace any damaged or shorted electrical wiring, harnesses, or connectors
- Repair damaged or defective up and down shift switch
- Clear all codes, test-drive the vehicle, and rescan to see if any codes reappear
Additional comments for consideration regarding the P0828 code
It is recommended to first check the switch location inside the passenger compartment for spilled liquids, clean, fix any damaged wiring if necessary, and retest before moving onto further aspects of the switch circuit.
Need help with a P0828 code?
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This article originally appeared on YourMechanic.com as P0828 OBD-II Trouble Code: Up and Down Switch Input Circuit High and was authored by Parker Hill.