What Does P0737 Mean?
The TCM has detected a general malfunction in the engine speed output circuit. The TCM outputs an engine speed signal (RPM) to other modules such as the instrument cluster or cruise control module, and this circuit is not functioning within normal parameters. The driver may notice an inoperative or erratic tachometer, cruise control malfunction, or other modules that rely on engine speed data behaving incorrectly.
Common Causes
35%
Open or shorted wiring in the TCM engine speed output circuit
25%
TCM internal output driver failure — unable to generate the engine speed signal
20%
Corroded or damaged connector at the TCM or receiving module
10%
Faulty receiving module loading down the output circuit
10%
Ground fault affecting the TCM output circuit reference
Diagnostic Steps
1
Verify the tachometer operation — if the tach is inoperative or erratic, this confirms the engine speed output signal is not reaching the instrument cluster.
2
Backprobe the engine speed output wire at the TCM connector with an oscilloscope while the engine is running — you should see a square wave signal proportional to engine RPM. No signal or a flat line indicates a TCM output driver failure.
3
Check the wiring from the TCM engine speed output pin to the receiving module(s) for continuity, shorts to ground, and shorts to power. Refer to the wiring diagram for pin identification.
4
Inspect all connectors in the circuit for corrosion, backed-out pins, or water damage. Pay special attention to connectors near the transmission where road spray is common.
5
If the wiring is intact, measure the signal at the receiving module end — if the signal is present at the TCM but absent at the destination, the wire has a break. If absent at the TCM, the TCM output driver has failed.
Estimated Repair Cost
$100 - $800
Parts + labor, varies by vehicle and location
The TCM has detected a general malfunction in the engine speed output circuit. The TCM outputs an engine speed signal (RPM) to other modules such as the instrument cluster or cruise control module, and this circuit is not functioning within normal parameters. The driver may notice an inoperative or ...
The most common cause of P0737 (TCM Engine Speed Output Circuit) is: Open or shorted wiring in the TCM engine speed output circuit
Typical repair costs for P0737 range from $100 to $800, depending on the vehicle, location, and whether you do it yourself or go to a shop.
The transmission itself typically shifts normally since the TCM still receives engine speed input internally. However, if cruise control or other safety systems rely on this signal, those features may be disabled. The vehicle can generally be driven safely to a repair shop.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0737 to identify the root cause.
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Quick Info
Category
Powertrain
System
Automatic Transmission / TCM Communication
Difficulty
Type
Generic (SAE)
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