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Subaru P1591

04/02 C.I.D. Nu

DriveUnknown.
ChargeUnknown.
ServiceService need is unknown from the supplied evidence. Contact a Subaru service provider if the code is present, particularly if warning messages or driveability concerns are also present.
Confidence95%

Quick answer

P1591 is listed in the supplied Subaru record as “04/02 C.I.D. Nu.” The supplied official bulletin-index evidence associates it with a 2002MY Subaru Impreza WRX manual transmission article, not with a specific EV fault description.

This page separates verified manufacturer/regulator evidence from supporting material. Unsupported causes, repairs or safety conclusions are not guessed.

Video guides

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DTC Subaru P1591 Short ExplanationMaxidot

Videos are supporting material and never override OEM or regulator evidence.

1. What does P1591 mean?

P1591 is listed in the supplied Subaru record as “04/02 C.I.D. Nu.” The supplied official bulletin-index evidence associates it with a 2002MY Subaru Impreza WRX manual transmission article, not with a specific EV fault description.

2. Technical explanation

Verified evidence identifies P1591 only as “04/02 C.I.D. Nu.” The official NHTSA-hosted Subaru Tech Tips/article-locator excerpts list “DTC P1591 2002MY Impreza WRX M/T” alongside that entry. The excerpt does not provide a fault definition, diagnostic procedure, cause, symptom, or repair.

3. What system is affected?

Not yet established by verified evidence.

4. How serious is this code?

Unknown.

5. Symptoms you may notice

  • Not yet established by verified evidence.

6. Possible causes

  • Not yet established by verified evidence.

7. Can I still drive the vehicle?

Unknown.

8. Can I charge the vehicle?

Unknown.

9. What you can safely do

  • Avoid assuming that P1591 has an EV or high-voltage-system meaning based on the supplied evidence.
  • Record the complete scan-tool results, including all stored and pending codes, and have the vehicle evaluated using Subaru service information applicable to its VIN and model year.

10. Step-by-step troubleshooting

  1. The verified evidence does not provide user-level troubleshooting steps.
  2. A qualified Subaru service provider can confirm whether the reported code is applicable to the vehicle and retrieve the relevant diagnostic information.

11. When to contact service

Service need is unknown from the supplied evidence. Contact a Subaru service provider if the code is present, particularly if warning messages or driveability concerns are also present.

12. What the service center may check

  • Confirm the vehicle VIN, model year, powertrain, and scan-tool module reporting P1591.
  • Confirm whether the code is applicable to the vehicle; the supplied official excerpt specifically references a 2002MY Impreza WRX manual transmission.
  • Use the applicable Subaru diagnostic information. Further diagnostic checks are not established by the supplied evidence.

13. Possible repair or resolution

  • Not yet established by verified evidence.

14. Affected vehicles

15. Related TSBs / service bulletins

  • NHTSA Manufacturer Communication PDF 11036794, published August 5, 2026: article-locator excerpt lists “DTC P1591 2002MY Impreza WRX M/T” and “04/02 C.I.D. Nu.”
  • NHTSA Manufacturer Communication PDF 11024859, published October 28, 2025: Subaru Tech Tips/article excerpt lists the same P1591 entry.
  • NHTSA Manufacturer Communication PDF 11024863, published October 28, 2025: Subaru Tech Tips/article excerpt lists the same P1591 entry.

16. Recall information

  • Not yet established by verified evidence.

17. Official manufacturer information

Official NHTSA-hosted Subaru source: https://static.nhtsa.gov/odi/tsbs/2026/MC-11036794-0001.pdf

19. Frequently asked questions

What does Subaru P1591 mean?

The supplied diagnostic record gives the canonical meaning as “04/02 C.I.D. Nu.” No further definition is established by the supplied verified evidence.

Is P1591 confirmed for Subaru EVs?

No. Although supplied applicability data includes several Subaru models, the supplied official bulletin excerpt specifically references a 2002MY Impreza WRX manual transmission. EV-specific relevance is not established by verified evidence.

Can I drive or charge with P1591?

Drive and charging safety are unknown in the supplied record.

20. Sources & verification

ReferenceVerified
Subaru P1591: 04/02 C.I.D. Nu | EV Diagnostics