Toggle Side Panel

Shopping Cart

No products in the basket.

Shopping Cart

No products in the basket.

Close search
Home / DTC / P1203 — Injector charge problem(low)

P1203 — Injector charge problem(low)

Detailed page for trouble code P1203.

34,405codes
59brands
11,914generic
22,491specific
All codes P-codes (Powertrain) B-codes (Body) C-codes (Chassis) U-codes (Network/User) Tesla Alerts
Reset
Code

P1203

MITSUBISHI P — Powertrain

Injector charge problem(low)

Brand: MITSUBISHI
Type: P — Powertrain
AI status
Completed
ready
Completed 100%
Page language: EN

Causes

  • Open or high-resistance injector circuit (wiring or connector)
  • Faulty fuel injector (partial clog, sticking pintle, weak coil)
  • Low fuel pressure or restricted fuel supply
  • Poor injector driver output from the ECM (low voltage/current)
  • Poor grounds or battery/charging system under-voltage
  • Corroded/loose connector or terminal

Symptoms

  • Rough idle or misfire under light load
  • Poor acceleration or power loss
  • Increased fuel trim corrections (long-term/short-term fuel trim changes)
  • Engine hesitation or stumble during throttle changes
  • Check Engine Lamp (MIL) illuminated and code P1203 stored
  • Possible fuel odor if injector is leaking (less likely for low-charge faults)

What to check

  • Read freeze frame and live data with a scan tool (injector pulse width, fuel trims, misfire counters, battery voltage)
  • Inspect wiring harness and connectors at the injector for damage, corrosion, or pin push-out
  • Measure fuel rail pressure and compare to specification
  • Measure injector coil resistance and compare to manufacturer spec
  • Use a noid light or oscilloscope to confirm injector driver pulses at the connector
  • Check battery voltage and engine ground connections

Signal parameters

  • Injector pulse width: typical idle values ~1–4 ms (varies by engine load and RPM); verify with vehicle-specific data
  • Injector coil resistance: refer to vehicle spec (typical range depends on design; check service manual)
  • Injector supply voltage: ~11–14.5 V with engine running (battery/charging system dependent)
  • Injector driver waveform: pulsed ground or positive switching depending on system; check for clean square/pulse waveform with oscilloscope
  • Fuel rail pressure: vehicle-specific (commonly 300–500 kPa for port-injected gasoline engines; check spec)

Diagnostic algorithm

  1. Retrieve and record all stored codes and freeze-frame data. Note which cylinder(s) are reported affected if available. Clear codes and perform a test drive to verify repeatability.
  2. Visually inspect injector connectors, harness, and pins for corrosion, looseness, or damage. Repair any wiring/connectors found defective.
  3. With key ON (engine off), backprobing connector: verify injector supply voltage (battery) at the injector harness and check for proper ground switching when cranking or commanding the injector via scanner.
  4. Measure injector coil resistance and compare to factory spec. Remove injector if necessary for accurate measurement. Replace injectors that are out of spec.
  5. Use a noid light or oscilloscope at the injector connector while cranking/running to confirm correct pulse presence and shape. If no pulse or abnormal waveform, further trace driver circuit or ECM.
  6. Check fuel rail pressure and flow. Repair or replace fuel pump, filter, or pressure regulator if pressure is below specification.
  7. If wiring, supply voltage, and fuel pressure are good but injector still under-delivering, perform an injector flow test or bench test. Replace injectors that fail flow/response tests.
  8. If an injector swap causes the fault to move to another cylinder, the injector is suspect. If the fault remains on the same cylinder after swapping, suspect wiring or ECM driver.
  9. Inspect and test engine grounds and charging system. Poor grounds or low voltage can cause weak injector drive.
  10. If all external checks pass and wiring to the injector is good, consult manufacturer service information for ECM driver tests and consider ECM repair/replacement as last resort.

Likely causes

  • Wiring/connectors to the affected injector(s) — corrosion, broken wire, poor pin contact
  • Clogged or partially failing injector causing reduced flow
  • Low system fuel pressure due to weak pump, clogged filter, or pressure regulator issue
  • Faulty injector driver transistor in ECM
  • Low battery/charging voltage or poor ground affecting injector drive

Fault status

⚠️ Status
P1203 — Injector charge problem (low). ECM detected injector delivery or charge lower than expected and set a fault. Check injector circuit, fuel supply, and control signals; repair as needed.
🟡 Repair difficulty: Medium
⏱️ Diagnostic time: 1.0 - 3.0 hours

Similar codes

P0200 P0201 P0202 P0203 P0204 P0205
406

Browse 406 MITSUBISHI manuals: repair procedures, diagnostics, wiring diagrams, component locations, service data and Labor Times by year, model and trim.

MITSUBISHI

Your experience will help others
+100 karma for a short comment :)
Keep it short and practical. Up to 500 characters.
Send to email

Report

Harassment or bullying behavior
Contains mature or sensitive content
Contains misleading or false information
Contains abusive or derogatory content
Contains spam, fake content or potential malware

Block Member?

Please confirm you want to block this member.

You will no longer be able to:

  • See blocked member's posts
  • Mention this member in posts
  • Invite this member to groups
  • Message this member
  • Add this member as a connection

Please note: This action will also remove this member from your connections and send a report to the site admin. Please allow a few minutes for this process to complete.

Report

You have already reported this .