Allison 1000 P0716 Input Speed Sensor: Diagnosis & Fix

P0716 on your Allison-equipped Duramax means the input speed sensor isn't reporting correctly. The TCM loses input RPM data and defaults to limp mode. Heres the diagnosis and fix.

What P0716 means

Input Speed Sensor (ISS) range/performance:

  • TCM measures input shaft RPM
  • Compares to engine RPM
  • Detects abnormal ratio
  • P0716 = sensor reporting wrong

    • Related codes:

  • P0717: ISS no signal
  • P0722: Output Speed Sensor (OSS)
  • P0700: TCM general fault

    • Symptoms

    • Limp mode (stuck in 3rd or 4th)
    • Harsh shifts
    • Sometimes intermittent
    • Tow/Haul light flashing
    • Speedometer may read correctly (different sensor)

    Why ISS fails

    Heat:

  • Mounted inside trans
  • High operating temp
  • Coil insulation degrades

    • Connector issues:

  • External harness corrosion
  • Internal harness chafe

    • Age:

  • Typical failure: 100k-200k miles
  • Earlier in tuned/tow trucks

    • Diagnosis

    Step 1: Verify code

  • P0716 specifically
  • P0717 = no signal at all

    • Step 2: Check connector

  • External harness at trans
  • Corrosion or damage
  • Reseat if loose

    • Step 3: Live data scan

  • ISS reading at various RPMs
  • Should track engine RPM proportionally

    • Step 4: Resistance test

  • Disconnect sensor
  • Ohm across terminals
  • Spec: 600-1200 ohms typical
  • Open or short = bad

    • Step 5: Signal voltage test

  • Backprobe with key on
  • Should show AC signal while turning

    • Cost

    ISS sensor only:

  • OEM AC Delco: $40-$90
  • Aftermarket: $25-$60

    • DIY install:

  • Drop pan: 1-2 hours
  • Sensor access typically requires pan drop
  • Time: 2-3 hours
  • Total: $80-$140

    • Shop install:

  • Parts: $40-$90
  • Labor: $250-$450
  • Total: $290-$540

    • Install procedure

    Step 1: Disconnect battery

    Step 2: Raise vehicle

    Step 3: Drain trans

  • ~12 quarts come out
  • Have replacement TES-295 ready

    • Step 4: Drop pan

  • 16 bolts
  • 10mm

    • Step 5: Locate ISS

  • Inside trans typically
  • Mounted to internal housing
  • 2-wire connector

    • Step 6: Replace sensor

  • Disconnect electrical
  • Remove mounting screw
  • Install new sensor
  • Reconnect electrical

    • Step 7: Reinstall pan

  • New gasket
  • Torque 89 in-lb

    • Step 8: Refill with TES-295

  • ~15 qts (some lost during)
  • Check level cold then hot

    • Step 9: Clear codes

  • Scan tool
  • Or wait 10 drive cycles

    • When ISS is NOT the fix

    • P0722 (output sensor) - different sensor
    • Wiring harness chafe (internal)
    • TCM driver fault (rare)
    • Read our Allison limp mode guide

    Pair with fluid service

    • Pan dropped anyway
    • Replace filter
    • Fresh TES-295
    • Magnet inspection (free diagnostic)

    Bottom line

    P0716 fix path:

  • Check connector first (free)
  • Replace ISS sensor ($40-$90)
  • Pan service included
  • Total under $300 DIY

    • Need Allison 1000 ISS sensor, TES-295 fluid, or rebuild parts? Shop our Allison catalog. OEM sensors, TES-295, complete rebuild kits. Free shipping over $70.

    Related:

    Related 1000 guides