Battery disconnected or replaced without maintaining KAM power, which is the most common trigger.; Blown fuse in the KAM constant power circuit, often in the engine bay or passenger compartment fuse box.; Corroded or loose battery terminals and ground connections that interrupt constant power.; Open or chafed wiring in the KAM feed circuit between the battery, fuse box, and ECM connector.; Faulty ignition switch or main relay that interrupts power to the ECM constant feed on some models.; Water intrusion or corrosion in the ECM connector or fuse box causing high resistance on the KAM pin.; Internal ECM fault where the KAM power input circuit fails, though this is less common than wiring issues.

DTC codes / Jaguar codes / P1600

P1600 · JaguarLoss Of Kam Power Circuit Open

Q: What does code P1600 mean?

Loss Of Kam Power Circuit Open. P1600 on a Jaguar means the engine control module (ECM) has detected an open circuit in the Keep Alive Memory (KAM) power supply, which is the constant battery feed that preserves adaptive learning and fault memory when the ignition is off. The ECM monitors this dedicated power input and sets the code when voltage is missing or interrupted, often after a battery disconnect, blown fuse, or wiring fault.

P1600 on a Jaguar means the engine control module (ECM) has detected an open circuit in the Keep Alive Memory (KAM) power supply, which is the constant battery feed that preserves adaptive learning and fault memory when the ignition is off. The ECM monitors this dedicated power input and sets the code when voltage is missing or interrupted, often after a battery disconnect, blown fuse, or wiring fault.

SystemPowertrain

Code typeJaguar specific

SeverityLow

Fix difficultyIntermediate

AreaComputer and output circuits

Symptoms you may notice

Often no symptoms besides the warning light, especially if the fault was triggered by a brief battery disconnect.
Engine may run roughly or idle poorly for a short period after startup while the ECM relearns adaptive fuel and idle strategies.
Transmission shift quality may feel harsh or inconsistent during the relearn process.
Intermittent no-start or crank-no-start if the KAM circuit is completely open and the ECM loses its memory.
Other unrelated trouble codes may appear or clear unexpectedly because the ECM cannot retain fault history.
Radio presets, clock, and other memory functions may reset if the same power feed supplies multiple modules.

Common causes, most likely first

Battery disconnected or replaced without maintaining KAM power, which is the most common trigger.
Blown fuse in the KAM constant power circuit, often in the engine bay or passenger compartment fuse box.
Corroded or loose battery terminals and ground connections that interrupt constant power.
Open or chafed wiring in the KAM feed circuit between the battery, fuse box, and ECM connector.
Faulty ignition switch or main relay that interrupts power to the ECM constant feed on some models.
Water intrusion or corrosion in the ECM connector or fuse box causing high resistance on the KAM pin.
Internal ECM fault where the KAM power input circuit fails, though this is less common than wiring issues.

How to diagnose and fix it

Clear the code and verify whether it returns immediately; if it was set by a recent battery service, no repair may be needed.
Check the battery voltage and condition, including terminals and grounds, and recharge or replace the battery if it is weak.
Locate and test the KAM fuse with a multimeter, replacing it only after identifying why it blew.
Inspect the KAM power wiring and connectors at the ECM for corrosion, looseness, or chafing, and repair as needed.
Back-probe the ECM KAM power pin with the ignition off to confirm battery voltage is present at the connector.
If voltage is missing at the ECM, trace the circuit back through the fuse box and ignition switch to find the open point.
If all wiring and fuses test good but the code persists, suspect an internal ECM fault and perform further module testing before replacement.

KAM power loss is not always a hard fault

Many P1600 codes are stored simply because the battery was disconnected during service, and the code clears and stays away after one drive cycle.
A weak or failing battery can cause intermittent KAM voltage drops that set P1600 without any obvious starting problem.
Technicians often overlook the KAM fuse because it may be labeled differently in the fuse box diagram, so check the owner's manual for the exact location.
After repairing the KAM circuit, the ECM may need a relearn drive cycle before idle and shift quality return to normal.
P1600 can be a secondary code triggered by a low-voltage event from a failing alternator, so check charging system output as well.

Can I keep driving with P1600?

It is generally safe to drive with P1600 because the fault affects memory retention rather than live engine control, but avoid ignoring repeated warnings if the engine runs poorly or stalls. Have the KAM circuit checked soon if the code returns after clearing, especially if you notice rough running or memory resets.

Tools that help

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Guidance is general and written for Jaguar vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.