Digital Transmission Range Sensor Out of Self-Test Range (Ford)
What does P1704 mean?
The P1704 code means the vehicle's onboard diagnostic system has detected: Digital Transmission Range Sensor Out of Self-Test Range (Ford). This is a moderate severity code.
Common Symptoms
- Check Engine Light on
- Transmission stuck in one gear
- No upshift or downshift
- Dashboard gear indicator incorrect
- Harsh engagement from Park to Drive
Probable Causes (Ranked by Likelihood)
- Failed digital transmission range sensor Very High
- Misaligned shift linkage High
- Corroded sensor connector on transmission Moderate
- Internal transmission wiring harness damage Low
Step-by-Step Diagnostic Procedure
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Monitor the digital TRS output on a scan tool while cycling through all gear positions.
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Check for proper shifter cable adjustment by verifying the transmission fully detents in each position.
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Inspect the digital TRS connector on the transmission case for fluid leaks, corrosion, or damage.
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Measure the digital TRS output pattern (binary code) at each position and compare to Ford specification.
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If the sensor is internal, the transmission pan must be removed to access and replace it.
Frequently Asked Questions
What is the difference between analog and digital TRS?
An analog TRS uses variable resistance, while a digital TRS uses a binary switch pattern. Ford uses digital sensors on many models for more precise gear position detection.
Can I replace the digital TRS without removing the transmission?
On many Ford transmissions, the digital TRS is externally mounted and can be replaced without removing the transmission. Some models require pan removal.
Will this code cause limp mode?
Possibly. If the PCM cannot determine the gear position, it may default to a safe gear (usually 3rd) and refuse to shift.