P1600

Code

MERCURY P — Powertrain

Loss of KAM Power Open Circuit

Brand: MERCURY

Type: P — Powertrain

Views: UK: 31 EN: 47 RU: 29

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Page language: EN

Blown or missing fuse supplying KAM power
Open or damaged wiring between fuse and PCM KAM terminal
Poor or corroded connector or terminal at PCM, fuse block, or ground
Aftermarket accessory incorrectly wired, backfeeding or pulling down KAM circuit
Failed or damaged PCM (rare)

Malfunction Indicator Lamp (MIL) illuminated and DTC stored
Loss of learned memory: radio presets, clock, adaptive transmissions, idle relearn
Stored trouble codes or readiness monitors cleared unexpectedly
Intermittent driveability issues or no crank/no start in systems that rely on retained data
Possible theft/anti-theft or immobilizer related messages or start problems

Scan for DTCs and freeze frame; record before clearing
Visual inspection of KAM fuse(s) and relevant fuse box area for corrosion or loose fuses
Verify battery voltage and overall charging system condition
Inspect PCM connector for bent pins, corrosion or pushed-out terminals
Backprobe KAM power terminal at PCM and check for proper voltage with key off/on as specified
Check for aftermarket installations that may be tied into constant power circuits

KAM (Keep-Alive Memory) voltage: approx. battery voltage (~11–14 V) present at PCM KAM pin with key OFF and key ON depending on vehicle design
Open-circuit condition: 0 V (or significantly below battery voltage) at PCM KAM terminal
Continuity: near 0 ohms between KAM fuse output and PCM KAM terminal; infinite/open if circuit broken
Voltage drop: negligible under light probe test; significant drop indicates poor connection or high resistance

Retrieve and record all stored DTCs and freeze frame data. Note recent repairs or battery disconnects.
Visually inspect KAM/constant power fuses (owner’s manual or wiring diagram to identify correct fuse). Replace any blown fuse and investigate cause of blown fuse.
With vehicle off, check battery voltage to ensure reliable test conditions. Recharge or replace battery if low.
Locate the PCM KAM power pin using wiring diagram. Backprobe that terminal and measure voltage with a digital multimeter with key OFF and key ON (as required). Expect battery voltage if KAM is a constant source.
If voltage is absent, trace wiring from the KAM fuse to the PCM: check continuity, inspect connectors, repair broken wires or corroded connectors. Wiggle test harness while monitoring voltage to find intermittent faults.
Check grounds and related power distribution points for corrosion or loose connections that could create an apparent open circuit.
Inspect for aftermarket devices tied into battery/KAM circuits. Disconnect such devices and re-test.
After repairing wiring or connectors, clear codes, cycle ignition and verify KAM voltage is present and stable, then re-scan for reappearance of P1600.
If wiring, fuses and connectors are good and KAM voltage still absent at PCM, consider replacing or bench testing the PCM as a last resort and ensure reprogramming/relearning as required.

⚠️ Status

Open circuit detected on Keep-Alive Memory (KAM) power supply to PCM — KAM power lost or not present.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours

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P1600 — Loss of KAM Power Open Circuit