P1738 on Mazda vehicles
P1738 is named on 34 Mazda model years (2016–2025): 128 manufacturer filings and 0 owner reports in NHTSA’s files, across CX-5, Mazda3, Mazda6, CX-3, CX-9 and 2 more.
Which Mazda model years name P1738
Source: NHTSA manufacturer communications and complaintsA model year is listed because the code is named in its own record — a bulletin filed against it, or an owner’s complaint about it — not because every one of these vehicles sets it. Counts are documents in NHTSA’s files, not failure rates.
Mazda filings that name P1738
Source: NHTSA manufacturer communicationsBulletins and campaigns Mazda filed with NHTSA whose summary names P1738. Quote the document number at the service desk — it is a diagnosis the maker has already written down.
- 05-005-16-3218 Service bulletin2016-07-07 · Engine
- SOME VEHICLES MAY EXPERIENCE THE CHECK ENGINE LIGHT AND AUTOMATIC TRANSAXLE WARNING LIGHT ON WITH ONE OR MORE OF THESE DTCS STORED IN THE TCM MEMORY (P0842, P0847, P0872, P0877, P0780, P1738).P0842:00 - OIL PRESSURE SWITCH NO. 1 (OIL PRESSURE SWITCH B) STUCK ONP0847:00 - OIL PRESSURE SWITCH NO. 2 (OIL PRESSURE SWITCH A) STUCK ONP0872:00 - OIL PRESSURE SWITCH NO. 3 (OIL PRESSURE SWITCH A) STUCK
- 05-005-16-3218 Service bulletin2016-07-07 · Engine
- SOME VEHICLES MAY EXPERIENCE THE CHECK ENGINE LIGHT AND AUTOMATIC TRANSAXLE WARNING LIGHT ON WITH ONE OR MORE OF THESE DTCS STORED IN THE TCM MEMORY (P0842, P0847, P0872, P0877, P0780, P1738).P0842:00 - OIL PRESSURE SWITCH NO. 1 (OIL PRESSURE SWITCH B) STUCK ONP0847:00 - OIL PRESSURE SWITCH NO. 2 (OIL PRESSURE SWITCH A) STUCK ONP0872:00 - OIL PRESSURE SWITCH NO. 3 (OIL PRESSURE SWITCH A) STUCK
- 05-002-15-3019F Service bulletin2015-12-03 · Engine
- SOME VEHICLES MAY EXPERIENCE THE CHECK ENGINE LIGHT AND AUTOMATIC TRANSAXLE WARNING LIGHT ON WITH ONE OR MORE OF THESE DTCS STORED IN THE TCM MEMORY (P0842, P0847, P0872, P0877, P0780, P1738). P0842:00 - OIL PRESSURE SWITCH NO. 1 (OIL PRESSURE SWITCH B) STUCK ON P0847:00 - OIL PRESSURE SWITCH NO. 2 (OIL PRESSURE SWITCH A) STUCK ON P0872:00 - OIL PRESSURE SWITCH NO. 3 (OIL PRESSURE SWITCH A)
- 05-004-18-3466 Service bulletin2018-04-16 · Engine And Engine Cooling
- Some vehicles may experience the check engine light and automatic transaxle warning light ON with one or more of these DTCs stored in the TCM memory (P0842, P0847, P0872, P0877, P0780, P1738). P0842:00 - Oil pressure switch No. 1 (oil pressure switch B) stuck on P0847:00 - Oil pressure switch No. 2 (oil pressure switch A) stuck on P0872:00 - Oil pressure switch No. 3 (oil pressure switch A) stuck
- 05-004-19-3466 Service bulletin2019-05-20 · Power Train
- Some vehicles may experience the check engine light and automatic transaxle warning light ON with one or more of these DTCs stored in the TCM memory (P0842, P0847, P0872, P0877, P0780, P1738). P0842:00 - Oil pressure switch No. 1 (oil pressure switch B) stuck on P0847:00 - Oil pressure switch No. 2 (oil pressure switch A) stuck on P0872:00 - Oil pressure switch No. 3 (oil pressure switch A) stu
- 05-003-20-3725 Service bulletin2020-07-09 · Engine
- Some vehicles may experience the check engine light and automatic transaxle warning light ON with one or more of these DTCs stored in the TCM memory (P0842, P0847, P0872, P0877, P0780, P1738). This is caused by the oil pressure switch A and/or B at the control valve body temporarily or permanently getting stuck due to contamination entering the passage. To correct the problem, some mass production
- 05-001-21-3826 Service bulletin2021-09-03 · Power Train
- Some vehicles may experience the check engine light and automatic transaxle warning light ON with one or more of these DTCs stored in the TCM memory (P0842, P0847, P0872, P0877, P0780, P1738). P0842:00 - Oil pressure switch No. 1 (oil pressure switch B) stuck on, P0847:00 - Oil pressure switch No. 2 (oil pressure switch A) stuck on, P0872:00 - Oil pressure switch No. 3 (oil pressure switch A) stuc
- 05-002-23 Service bulletin2023-05-17 · Power Train
- Some vehicles may experience the check engine light and automatic transaxle warning light ON with one or more of these DTCs stored in the TCM memory (P0842, P0847, P0872, P0877, P0780, P1738).
- 05-001-25a Service bulletin2025-11-23 · Power Train
- Some customers may see the A/T warning light on during (or immediately after) engine start-up with DTCs P073D:00-TCM / P1738:00-TCM stored. P073D:00-TCM: Turbine/input shaft speed sensor: Sensor output range malfunction P1738:00-TCM: Automatic transaxle internal malfunction This concern is caused by improper TCM logic. To eliminate this concern, the TCM control software has been modified to change
What P1738 means
Source: SAE J2012 / OBD-IIP1738 is a manufacturer-specific code: the second character is a 1, which under the OBD-II standard hands the definition to whoever built the vehicle. The same code can mean one thing on a Ford and something unrelated on a Hyundai. Any site that prints a single definition for it is guessing.
A stored code names the test that failed, never the part that caused it. The record above is what Mazda and its owners have filed about it; the code’s page across every make has the whole file.
Common questions
Source: NHTSA files and the OBD-II standardIs P1738 a known problem on Mazda vehicles?
It is a documented one: NHTSA's files hold 128 manufacturer filings and 0 owner reports naming P1738 on 34 Mazda model years (2016–2025). Whether it is a problem on one particular car is a diagnosis, not a count — but a bulletin that names the code on your model year is the place to start.
Which Mazda models does P1738 appear on most?
2016 CX-5 (9 documents), 2016 Mazda3 (9 documents), 2016 Mazda6 (9 documents).
Does P1738 on a Mazda mean it is recalled?
No. Recalls are filed by campaign and matched by VIN; no recall is triggered by a scan tool. Check the VIN at nhtsa.gov/recalls, or open the model year's page here for the campaigns filed against it.