P0654

Code

LAND ROVER P — Powertrain

Engine Speed Output Circuit

Brand: LAND ROVER

Type: P — Powertrain

Views: UK: 30 EN: 43 RU: 42

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Page language: EN

Causes

Open or short in engine speed output wiring between ECM and instrument cluster/other modules
Corroded, loose or damaged connector or terminal at ECM, cluster or intermediate modules
Failed ECM/PCM output driver transistor
Faulty instrument cluster, tachometer or intermediate module that receives the speed signal
Poor ground or low battery supply to ECM or receiving module
Water ingress or damage to cabling/harness

Symptoms

Check Engine MIL illumination and stored P0654 code
Erratic or no tachometer (engine RPM gauge) reading
Some systems that rely on engine speed (cruise control, shift logic) may operate incorrectly
Possible drivability complaints if another sensor affected
No start or crank issues are less common but possible if related circuits damaged

What to check

Read and record all stored DTCs and freeze-frame data with a scanner; note other RPM-related codes (e.g., crank/cam sensor codes)
Confirm actual engine RPM vs. scanner RPM value while cranking and running
Visually inspect connectors and wiring for the ECM, instrument cluster and any modules that use engine speed
Check related fuses and power/ground feeds for ECM and instrument cluster
Backprobe the engine speed output pin at the ECM and at the receiving module to compare signals
Use an oscilloscope to verify waveform shape, amplitude and frequency of the RPM output

Signal parameters

Type: Pulsed digital/square wave or TTL/Hall-effect style signal (varies by model)
Amplitude: typically 0–5 V for logic-level signals; some instrument inputs expect 0–12 V square pulses — check manufacturer data
Frequency: proportional to engine RPM (frequency increases as RPM increases)
At key ON engine OFF: signal may be present as idling pulses or inactive depending on design
Fault indications: open circuit = no pulses (0 V); short to battery = steady 12 V; short to ground = 0 V; erratic amplitude or missing pulses indicate wiring/driver/receiver fault

Diagnostic algorithm

Verify code and any related codes using a diagnostic scanner; record live RPM and freeze-frame.
Inspect visually: connectors, pins, harness for damage, corrosion or water intrusion between ECM and cluster/receivers.
Check fuses and power/ground circuits for ECM and receiving module(s). Repair any faulty power/ground first.
With a multimeter, backprobe the ECM engine speed output pin and the receiving module pin; confirm presence or absence of voltage and compare.
Use an oscilloscope to inspect waveform while cranking and running; verify clean square wave or expected waveform shape and amplitude.
If waveform is missing at the ECM but present at the cluster (unlikely), suspect harness; if present at ECM but not at cluster, suspect wiring/connector between them.
Perform continuity and short-to-ground/short-to-B+ tests on the wiring harness with battery disconnected. Repair any opens/shorts.
If wiring and connectors are good but signal is incorrect at ECM output, consider ECM output driver failure. Confirm by substituting a known-good ECM or by manufacturer-recommended ECM tests.
If ECM output is correct but cluster receives no/incorrect signal, test/repair or replace instrument cluster or intermediate module as required.
Clear codes, perform a road test and re-scan to confirm the repair. Monitor RPM signal and related systems for proper operation.

Likely causes

Damaged or disconnected connector/pin at ECM or instrument cluster
Open or shorted harness between ECM and cluster
Corrosion or contamination causing intermittent signal
Failing ECM/PCM output driver
Faulty instrument cluster or tachometer input circuit

Fault status

⚠️ Status

P0654 — Engine Speed Output Circuit: The control module detects an open, short or implausible engine speed output signal. Verify signal integrity, wiring and module inputs/outputs.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.5 hours

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