P1919

Code

Generic P — Powertrain

Powertrain Control Module Internal Fault

Brand: Generic

Type: P — Powertrain

Views: UK: 9 EN: 9 RU: 7

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Page language: EN

Causes

PCM internal hardware failure (processor, memory, EEPROM/flash)
Corrupted or failed PCM software/firmware
Intermittent or low battery/charging system voltage (voltage dips/spikes)
Poor or corroded power/ground connections to the PCM
Water intrusion, physical damage, or corrosion at the PCM
Failed PCM connectors, broken pins, or wiring short to power/ground

Symptoms

Malfunction Indicator Lamp (MIL/CEL) illuminated
One or more drivability issues: limp mode, reduced engine power, stalls, hard starting, or no-start
Loss of communication with the PCM on diagnostic tool (CAN/serial comm errors)
Multiple unrelated codes stored or intermittent/random fault behavior
Some vehicle systems disabled or functioning incorrectly

What to check

Read all stored and pending codes and note freeze-frame data and occurrence counts
Verify battery voltage at rest and during cranking (11.5–14.5 V typical) and inspect charging system
Check for additional communication codes (U-codes) that indicate bus problems
Inspect PCM connector and pigtail for corrosion, bent/broken pins, water intrusion, or heat damage
Verify all PCM power feeds and grounds with a multimeter for proper voltage and continuity
Check related fuses and relays supplying the PCM

Signal parameters

PCM main supply voltage (Key ON, Engine OFF): ~11.5–14.5 V (should be stable)
PCM ground continuity: near 0 Ω to chassis ground
CAN bus idle voltage (each line to ground) and differential: approx. 2.5 V nominal per line, correct differential and data activity (verify termination ~60 Ω across CAN lines)
5 V reference (where used) should be stable and within manufacturer tolerance
Scan tool communications: consistent polling responses from PCM (no timeouts)

Diagnostic algorithm

Retrieve all DTCs, freeze-frame, and live data. Record any related U-codes or multiple internal module codes.
Verify battery state-of-charge and charging system operation. Recharge or replace weak battery before further testing.
Visually inspect PCM and connector for moisture, corrosion, physical damage, or evidence of overheating. Repair or replace damaged harness as needed.
With connector attached, verify PCM power and ground circuits for correct voltage and continuity per wiring diagram. Repair poor connections, grounds, or blown fuses/relays.
Check the vehicle communication network (CAN/ISO) for correct idle voltages, termination, and activity. Repair wiring faults if bus errors present.
Clear codes and perform a controlled drive cycle. If code does not return, monitor for recurrence and associated symptoms.
If wiring and supply/ground are good and the fault returns, confirm with a known-good scan tool and check for available PCM software updates or recalls/TSBs.
Reflash or update PCM software only if confirmed by manufacturer procedure. Follow proper battery charger/voltage-sustaining procedures during reprogramming.
If reflash fails to resolve and diagnostics point to internal module failure, arrange for module replacement/programming. Preserve immobilizer/anti-theft data and follow OEM relearn/programming steps.
If replacing the PCM, verify correct part number and perform required configuration, coding, and relearn procedures. Re-scan for related codes after replacement.

Likely causes

Battery voltage out of range during module operation or reflash
Loose, corroded, or missing PCM ground or power feed
Previous repair work disturbed PCM connector or wiring
Failed internal PCM component (processor, memory) after age or water exposure
Incomplete or corrupted reprogramming update

Fault status

⚠️ Status

Internal PCM fault detected. The module has flagged an internal hardware or software error in its diagnostics. This may set the MIL and can affect powertrain control and communications. Further electrical and module-level tests are required before replacing the module.

🔴 Repair difficulty: Hard

⏱️ Diagnostic time: 1.5-3.5 hours