A vehicle’s ECU relies on a number of sensors to tell it what the vehicle is doing, and what gear the driver has selected. If the driving situation and gear selection do not meet preset parameters, a P0821 DTC will be set.
Need a replacement transmission? Get an estimate for replacement transmissions and local installation. Look up your transmission model by vehicle make and model.
What Transmission Do I Have?
How Serious is the Code?
It’s important for the ECU to know what gear has been selected by the driver, so a P0821 diagnostic trouble code is rather important. Particularly if that ECU puts the transmission into limp load mode (it will be restricted to a single forward gear).
Symptoms
Symptoms of a P0821 include:
- Unusually hard shifts
- ‘Stuck’ in a gear
Causes
- Damaged wiring and/or connectors
- Misadjusted transmission range sensor
- Faulty transmission range sensor
How to Diagnose the Code?
One of the main causes of a P0821 OBDII trouble code is an electrical fault. So a mechanic should start by examining the condition of the wiring and connectors. If no problems are found, the transmission range sensor will need to be tested.
Need a replacement transmission? Get an estimate for replacement transmissions and local installation. Look up your transmission model by vehicle make and model.
What Transmission Do I Have?
What Repairs Will Fix P0821?
- Repair or replace damaged wiring/connectors
- Adjust or replace transmission range sensor
Related Codes
- P0820 – Gear Lever X-Y Position Sensor Circuit
P0822 – Gear Lever Y Position Circuit
P0823 – Gear Lever X Position Circuit Intermittent
P0824 – Gear Lever Y Position Circuit Intermittent
