U0622

Code

Generic U — Network/User

Lost Communication With Exhaust Gas Temperature Sensor Bank 2 Sensor 2

Brand: Generic

Type: U — Network/User

Views: UK: 23 EN: 37 RU: 26

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Page language: EN

Causes

Open, shorted or damaged sensor wiring harness (power, ground, signal)
Corroded, bent or loose connector pins at the EGT sensor or harness junction
Failed EGT sensor (thermocouple/thermistor or integrated electronics)
CAN bus or dedicated serial data line faults (short to voltage/ground, missing termination)
Intermittent connection from heat damage (exhaust heat) or contamination
Faulty PCM/ECM or other control module providing/receiving the signal

Symptoms

Malfunction Indicator Lamp (MIL)/Check Engine light illuminated
Stored U0622 and possibly related U-codes or sensor codes
Loss of exhaust temperature data on scan tool for Bank 2 Sensor 2
Limited aftertreatment control or reduced regeneration capability (DPF/DEF systems)
Reduced performance or limp-home mode in some vehicles (if ECU disables functions)
Intermittent operation that may coincide with vibrations or engine heat cycles

What to check

Read and record all stored DTCs and freeze frame data; note if code is current or historic
Use a scan tool to monitor live data for EGT Bank 2 Sensor 2 and check for valid temperature values or ‘no data’
Inspect the sensor connector and wiring harness visually for heat damage, corrosion, chafing or broken wires
Check for other network communication U-codes that indicate a broader bus problem
Backprobe the sensor connector to verify reference power (if applicable), ground, and signal presence with an appropriate meter
Check CAN/high-speed data line voltages and bus termination (approx. 2.5V common-mode, ~2.5V/0.5V differential on high/low depending on vehicle) using a scope if available

Signal parameters

EGT signal type: thermocouple, thermistor or integrated electronic sensor (varies by manufacturer)
Typical thermocouple voltage: millivolt-level proportional to temperature (manufacturer-specific)
Typical thermistor: resistance changes with temperature (ambient ~kΩ range depending on design)
CAN/data bus: expected message frequency (e.g., 1–10 Hz) and defined message ID for EGT data (refer to vehicle wiring/data manual)
Power/ground: switched or ignition-referenced 5V/12V feed and a solid ground — verify nominal voltages per vehicle specifications
CAN bus idle voltages: CAN_H ≈ 2.5–3.5 V, CAN_L ≈ 1.5–2.5 V with correct termination (~60 Ω across H/L)

Diagnostic algorithm

Retrieve all codes and freeze frame with a scan tool. Note related U or P codes and occurrence frequency (current vs. history).
Attempt to reproduce: monitor live EGT Bank 2 Sensor 2 data while performing conditions that normally trigger the code (warm engine, drive cycle).
Visual inspection: check sensor, connector, and harness routing for heat, abrasion, corrosion, or evidence of rodent damage. Check nearby exhaust components for contact points.
Check connector: disconnect and inspect pins for corrosion or damage. Clean and reseat or replace connector if contaminated. Re-scan for code disappearance.
Backprobe and measure: with connector connected, measure sensor reference voltage (if present), ground continuity, and signal voltage or resistance while engine is cold and warmed (follow vehicle-specific values).
Wiggle test: with live data displayed, wiggle harness and connectors from sensor to PCM to find intermittent breaks; if data drops out during motion, trace and repair wiring.
CAN/network check: if the EGT sensor is networked, verify presence of EGT message on the bus with a scan tool or scope. Measure CAN_H/CAN_L voltages and check for correct termination and no shorts to Vb or ground.
Isolate sensor: if wiring/connector and bus look good, compare sensor readings (or resistances) to specification. If out of spec, replace sensor. If sensor is in spec and no data present, trace wiring to module or check module behavior.
Swap/compare (if applicable): if vehicle has an identical sensor (other bank or upstream) and wiring allows, swap sensors to see if fault follows sensor or remains with location.
Repair and verify: repair wiring/connector or replace sensor/module as required. Clear codes and perform drive cycle to confirm the code does not return and EGT data is restored.
If intermittent or no fault found: consult wiring diagrams, check for updated PCM software or technical service bulletins (TSBs), and consider module bench testing or dealer-level diagnostics.

Likely causes

Connector corrosion or pin damage at bank 2 sensor 2 harness
Broken or chafed wiring in harness near exhaust or flex areas
Failed EGT sensor from heat cycling or contamination
Lost CAN/data message due to bus wiring fault or missing termination
PCM/ECM communication fault or internal failure (less common)

Fault status

⚠️ Status

PCM reports no valid/existing data stream from Exhaust Gas Temperature Sensor Bank 2 Sensor 2 (lost or invalid communication). Data missing or out-of-range for defined timeout period.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1-3 hours