Code
P1600
PORSCHE
P — Powertrain
Voltage supply
Views:
UK: 8
EN: 9
RU: 4
AI status
Completed
Completed
100%
Causes
- Low or weak battery
- Poor or corroded battery terminals/connections
- Faulty or slipping alternator/voltage regulator
- Blown fuse or faulty power/ignition relay (module supply fuse/relay)
- Open, shorted or damaged wiring to the control module power pin
- Poor or corroded ground connection(s)
Symptoms
- Malfunction Indicator Lamp (MIL) illuminated
- Intermittent or no-start condition
- Intermittent loss of communication with control modules on diagnostic tool
- Erratic engine or transmission behavior
- Battery/charging system warning lamp
- Other voltage-related DTCs present
What to check
- Read stored codes and freeze-frame data with a scan tool; check for related codes
- Measure battery resting voltage (engine off) and voltage under cranking
- Measure charging system voltage with engine running (13.5–14.8 V expected)
- Visually inspect battery terminals, cable condition and ground straps for corrosion or looseness
- Inspect and test fuses and relays in the power distribution center related to the affected module
- Back-probe and measure voltage at the module's power supply pin(s) and main ground with key on and engine running
Signal parameters
- Battery resting voltage: typically 12.4–12.8 V (acceptable >=12.0 V)
- Cranking voltage: normally >= 9.5–10.5 V depending on model and condition
- Charging voltage (engine running): typically 13.5–14.8 V
- Module supply pin voltage: should be within ~0.1–0.5 V of battery B+ with key on/run
- Ground resistance: low (near 0 Ω); any high resistance can cause voltage drop
Diagnostic algorithm
- Capture codes, freeze-frame, and live data. Note when the fault occurred and any concurrent codes.
- Verify battery condition: measure open-circuit voltage and perform a battery load test or conductance test. Replace weak battery first.
- Check charging system: measure alternator output at battery terminals with engine running (target 13.5–14.8 V). Repair charging faults if present.
- Visually inspect and clean battery terminals, cable ends, and main ground connections. Tighten to specification.
- Inspect fuses and power/ignition relays for the affected module; replace suspect items and retest.
- Back-probe the module power supply pin(s) and main ground with key on/run. Compare readings to battery voltage. Look for voltage drop >0.5 V.
- With scan tool connected, wiggle wiring harnesses and connectors (engine off and running as appropriate) while monitoring supply voltage and module communication to reproduce intermittent faults.
- If a voltage drop or open is found, trace and repair wiring: repair corroded terminals, replace damaged wires, or repair grounds. Use wiring diagrams to isolate circuits.
- Clear codes and perform functional test/road test. Re-scan for return of P1600 or related codes.
- If wiring, power and grounds test good and problem persists, consider module internal fault or intermittent internal supply failure—refer to manufacturer guidance before replacing module.
Likely causes
- Weak battery or poor battery connections
- Corroded or loose ground strap(s)
- Blown fuse or faulty power relay supplying the module
- Open or high-resistance wire between battery/ignition and module power pin
- Alternator/charging system not maintaining proper voltage
Fault status
Status
Control module detected an out-of-spec or interrupted voltage supply to its power circuit. Fault stored when supply voltage, ground or related power circuit is abnormal or failing.
Repair difficulty: Medium
Diagnostic time: 1.0-3.0 hours
Similar codes
Your experience will help others
+100 karma for a short comment :)
Was this AI description helpful?
Your feedback helps improve AI descriptions.
👍 Like
0
👎 Dislike
0
Send to email