P2740 — Transmission Fluid Temperature Sensor "B" Circuit

powertrain (engine/transmission)

Is it safe to drive?

Drive with caution Drive only if the transmission still shifts predictably, and avoid highway speeds. Driving with slipping or limp mode accelerates internal wear — every kilometre can add to the final repair bill.

How to diagnose with an OBD scanner

Read the code and freeze frame Connect an OBD2 scanner, confirm P2740 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
Check for companion codes and TSBs Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many P0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
Inspect wiring and connectors Visually inspect the wiring harness and connectors related to the automatic transmission control for damage, corrosion, chafing or poor contact.
Subsystem check Check transmission fluid level and condition — dark, burnt fluid points to internal wear.
Subsystem check Read transmission-specific codes and live data (solenoid states, input/output speed) with a capable scanner.
Verify the repair Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm P2740 does not return.

Approximate repair cost

Repair cost depends on which component actually failed. Typical scenarios for P2740 (parts and labor, USD, independent shop rates): Replace a shift solenoid: $300–$800; Transmission rebuild or replacement: $2,500–$5,500; Valve body repair or replacement: $700–$1,500; Transmission fluid service: $150–$350. Overall, fixing P2740 usually costs between $150 and $5,500. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.

Common questions

Is it safe to drive with P2740?

Drive only if the transmission still shifts predictably, and avoid highway speeds. Driving with slipping or limp mode accelerates internal wear — every kilometre can add to the final repair bill.

What does OBD2 code P2740 mean?

Transmission Fluid Temperature Sensor "B" Circuit (P2740): a powertrain (engine/transmission) fault affecting the automatic transmission control. Short, gentle driving to a shop is usually possible. Most often caused by faulty transmission speed sensor, wiring or connector faults in the valve body harness, valve body wear.

What is the most common cause of P2740?

The most common causes are: faulty transmission speed sensor, wiring or connector faults in the valve body harness, valve body wear.

What are the symptoms of P2740?

Drivers most often notice: slipping between gears, shuddering at highway speed, transmission stuck in one gear (limp mode), no movement in severe cases.

Will P2740 clear itself?

Sometimes P2740 clears after a few drive cycles if the fault was intermittent — for example a loose connector or a tank of bad fuel. The underlying cause usually remains, so the code tends to return. Clear it once; if it comes back, diagnose rather than erase it repeatedly.

What does P2740 mean?

P2740 (Transmission Fluid Temperature Sensor "B" Circuit) is stored when self-diagnostics detect abnormal readings or behaviour of the automatic transmission control. It belongs to the powertrain (engine/transmission) category.

To set P2740, the control module compares live readings of the automatic transmission control against calibrated limits, usually over several drive cycles. Alongside the code it stores a freeze frame — a snapshot of rpm, load, coolant temperature and vehicle speed at the moment of failure. Reading that snapshot first saves diagnostic time.

Common symptoms of P2740

slipping between gears
shuddering at highway speed
transmission stuck in one gear (limp mode)
no movement in severe cases
harsh or delayed shifting

What causes P2740?

low or degraded transmission fluid
internal mechanical wear (clutches, torque converter)
faulty transmission speed sensor
failed shift or pressure control solenoid

How to diagnose P2740

Connect an OBD2 scanner, confirm P2740 is stored, and save the freeze frame data — it shows engine conditions when the fault was detected.
Related codes often reveal the real root cause. Also check manufacturer technical service bulletins (TSB) for your make and model — many P0xxx issues have factory fixes or software updates. Search by VIN on the manufacturer site or nhtsa.gov.
Visually inspect the wiring harness and connectors related to the automatic transmission control for damage, corrosion, chafing or poor contact.
Check transmission fluid level and condition — dark, burnt fluid points to internal wear.
Read transmission-specific codes and live data (solenoid states, input/output speed) with a capable scanner.
Clear the code, complete a full drive cycle including the conditions from the freeze frame, and confirm P2740 does not return.

How to fix P2740

Start with the cheapest and most common causes before replacing expensive parts:

Replace a shift solenoid — $300–$800
Transmission rebuild or replacement — $2,500–$5,500
Valve body repair or replacement — $700–$1,500
Transmission fluid service — $150–$350

How much does it cost to fix P2740?

Repair cost depends on which component actually failed. Typical scenarios for P2740 (parts and labor, USD, independent shop rates):

Replace a shift solenoid: $300–$800
Transmission rebuild or replacement: $2,500–$5,500
Valve body repair or replacement: $700–$1,500
Transmission fluid service: $150–$350

Overall, fixing P2740 usually costs between $150 and $5,500. An accurate diagnosis before buying parts saves money — the most expensive scenario is rarely the first one to check.

Can you drive with P2740?