Exhaust Gas Temperature Sensor Circuit High Bank 1 Sensor 2

What P2033 means

Exhaust gas temperature sensors are thermistors placed in the exhaust and after-treatment stream — most commonly on diesels such as Ford's 6.7L Power Stroke, where the PCM labels the sensors EGT11, EGT12, EGT13 and EGT14 along the DOC/DPF/SCR system. On these sensors resistance falls as temperature climbs, so a hot exhaust returns a low signal voltage and a cold or disconnected sensor pushes the signal toward the reference-voltage rail. P2033 is the 'circuit high' code for the bank 1, sensor 2 position (EGT12): the PCM sets it when that sensor's signal voltage stays above its ceiling — on the 6.7L Power Stroke, greater than about 4.90 volts for more than roughly 15 seconds. Electrically that means an open in the signal or return wire, a short to voltage, or a sensor that has failed and pins its output high. Because the PCM relies on EGT readings to time and protect diesel particulate filter (DPF) regeneration and to guard against over-temperature, losing a valid EGT12 signal typically drops the truck into a reduced-power derate mode until the fault clears.

Symptoms

• Check-engine light on, with the code stored in continuous (keep-alive) memory
• Reduced engine power or a limp/derate mode that caps output
• A dash message (for example a powertrain or exhaust-system warning) that may linger even after the repair until a drive cycle completes
• Disabled or incomplete DPF regeneration, sometimes with more frequent regen attempts or a filling particulate filter
• Higher exhaust temperatures going unmonitored, and on some trucks poorer fuel economy
• No obvious drivability change at all in mild cases — just the light and a logged code

Common causes

• Open circuit in the EGT12 signal or signal-return wire (the most common trigger for a 'circuit high' reading)
• EGT12 sensor connector unplugged, corroded, or with spread/backed-out terminals
• Signal wire shorted to a voltage source or to the sensor reference (VREF) rail
• Damaged or internally failed EGT sensor that pins its output high
• Chafed, melted, or heat-damaged harness near the exhaust that broke the circuit
• Moisture or road-salt corrosion in the connector raising circuit resistance
• Rarely, a PCM/driver-side fault or reference-voltage problem on the shared circuit

Severity & driving advice

Severity: Moderate — Not an immediate hazard, but on diesels the truck often derates to reduced power and DPF regeneration is disabled until the EGT sensor circuit is fixed.

Can I drive? Usually drivable short-term, but expect reduced power in derate mode and stalled DPF regeneration. Fix it promptly so the particulate filter keeps regenerating and over-temperature protection stays intact.

Diagnostic approach

1. Read codes and record freeze-frame — Retrieve all stored, pending, and continuous-memory codes and note the freeze-frame conditions. Confirm P2033 specifically, and check for companion EGT codes (open, short-low, or range/performance faults on the same or neighboring sensors) that can point to a shared harness or connector problem.
2. Watch the live EGT12 signal — With a scan tool, monitor the bank 1 sensor 2 EGT parameter (Ford calls it EGT12_V). Key-on engine-off on a cold engine, all EGT sensors should read close together near ambient. A value pinned at or above roughly 4.90 volts — the threshold Ford uses to set P2033 after about 15 seconds — while the others sit lower confirms a circuit-high condition on that one sensor rather than a real over-temperature.
3. Inspect the sensor, connector, and harness — Locate the EGT12 sensor at its position in the exhaust/after-treatment stream and unplug the connector. Look for corrosion, moisture, spread or pushed-back terminals, and follow the harness for chafing, melting, or pinch points near the hot exhaust. Wiggle-test the connector and harness while watching live data to expose an intermittent open that trips the code.
4. Check the signal circuit for an open — With the sensor unplugged and the key on, an open EGT signal circuit typically floats high toward the reference rail — that is exactly what drives a circuit-high code. Key off, measure resistance end-to-end on the signal and signal-return wires between the sensor connector and the PCM; a very high or infinite reading confirms the open. Also verify the return/ground path is intact, since a lost ground can force the signal high.
5. Test for a short to voltage — Disconnect the sensor and, with the key on, check the signal wire for unexpected voltage with the PCM connector also disconnected. Any source voltage present on the isolated signal wire indicates a short to power or to the VREF circuit that would hold the reading above the P2033 ceiling. Repair the shorted section before re-testing.
6. Confirm the sensor, then repair and verify — If the wiring, connector, reference, and ground all check out, the EGT sensor itself is the likely fault — an EGT thermistor should read a sensible resistance that changes with temperature, not an open or pinned value. Replace the faulty sensor or repair the wiring, clear the code, then complete the appropriate drive cycle so the PCM re-runs its monitors, clears any lingering dash message, and confirms P2033 does not reset and derate does not re-engage.

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