Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Digital Transmission Range (TR) Sensor Diagnosis Chart
2004 Mazda B4000 4WD V6-4.0L SOHCSECTION Digital Transmission Range (TR) Sensor Diagnosis Chart
Digital Transmission Range (TR) Sensor Diagnosis Chart
A. TRV is the voltage at the PCM pin 64 (TR3A Circuit) to signal return.
B. "In Between" reading could be caused by a shift cable or digital TR sensor misaligned or a digital TR sensor circuit failure of TR1, TR2, TR3A, or TR4.
C. TR_D: 1 =Open Digital TR switch, 0=Closed Digital TR switch.
D. Breakout Box Readings: Taken from PCM signal pins for TR1, TR2, TR3A, TR4 to signal return.
^ Voltages for TR1, TR2, TR4: 0=0.0 volts (circuit shorted to ground).
^ 1=9.0 - 14.0 volts (open circuit). Voltage for TR3A: 0=0.0 volts (circuit shorted to ground).
^ 1=1.3 - 1.8 volts (open circuit).
^ 0.0 volts=Closed Digital TR switch.
^ 1.3 - 1.8 volts=Open Digital TR switch.
E. TR4, TR3A, TR2, and TR1 are all closed in PARK (shorted to signal return), so PARK is a good position to check for intermittent open circuits.
F. TR4, TR3A, TR2, and TR1 are all open in OVERDRIVE, so OVERDRIVE is a good position to check for shorts to ground. To determine the shorted components while observing TR_D, unplug the TR and see if the short goes away.
G. If the short is still present, unplug the transmission harness and see if the short goes away.
H. It the short is still present, then the short is in the PCM or vehicle harness. Remove the suspect circuit(s) wire from the PCM vehicle harness.
I. If the short is still present, then the PCM has an internal failure, otherwise the failure is in the vehicle harness.
A. TRV is the voltage at the PCM pin 64 (TR3A Circuit) to signal return.
B. "In Between" reading could be caused by a shift cable or digital TR sensor misaligned or a digital TR sensor circuit failure of TR1, TR2, TR3A, or TR4.
C. TR_D: 1 =Open Digital TR switch, 0=Closed Digital TR switch.
D. Breakout Box Readings: Taken from PCM signal pins for TR1, TR2, TR3A, TR4 to signal return.
^ Voltages for TR1, TR2, TR4: 0=0.0 volts (circuit shorted to ground).
^ 1=9.0 - 14.0 volts (open circuit). Voltage for TR3A: 0=0.0 volts (circuit shorted to ground).
^ 1=1.3 - 1.8 volts (open circuit).
^ 0.0 volts=Closed Digital TR switch.
^ 1.3 - 1.8 volts=Open Digital TR switch.
E. TR4, TR3A, TR2, and TR1 are all closed in PARK (shorted to signal return), so PARK is a good position to check for intermittent open circuits.
F. TR4, TR3A, TR2, and TR1 are all open in OVERDRIVE, so OVERDRIVE is a good position to check for shorts to ground. To determine the shorted components while observing TR_D, unplug the TR and see if the short goes away.
G. If the short is still present, unplug the transmission harness and see if the short goes away.
H. It the short is still present, then the short is in the PCM or vehicle harness. Remove the suspect circuit(s) wire from the PCM vehicle harness.
I. If the short is still present, then the PCM has an internal failure, otherwise the failure is in the vehicle harness.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.