Acura OBD/OBD2 Codes >> 2.5TL (1995 – 1998)

ModelYearEngine identificationSystem

General information

  • Refer to the front of this manual for general test conditions, terminology, detailed descriptions of wiring faults and a general trouble shooter for electrical and mechanical faults.
  • Engine control module (ECM) incorporates self-diagnosis function.
  • Malfunction indicator lamp (MIL) will illuminate if certain faults are recorded.
  • ECM operates in backup mode if sensors fail, to enable vehicle to be driven to workshop.
  • Trouble codes can be displayed by using a Scan Tool connected to the data link connector (DLC) 1 [1] or by the malfunction indicator lamp (MIL) with the service check connector jumped [1] [2].

NOTE: The use of a Scan Tool is essential to obtain full diagnostic information.


  • Ensure ignition switched OFF.
  • Jump service check connector terminals [1] [2].
  • Switch ignition ON.
  • Check MIL is flashing.
  • Trouble codes 1-9 are indicated as follows:
o Individual short flashes display trouble code [1] [A].
o A short pause separates each flash [2] [B].
o A long pause separates each trouble code [2] [C).
o For example: Trouble code 3 displayed [2].
  • Trouble codes greater than 9 are indicated as follows:
o Long flashes indicate the ‘tens’ of the trouble code [3] [A].
o Short flashes indicate the ‘units’ of the trouble code [3] [C].
o A short pause separates each flash [3] (B).
o A long pause separates each trouble code [3] [D].
o For example: Trouble code 12 displayed [3].
  • Count MIL flashes and compare with trouble code table.
  • Switch ignition OFF.
  • Remove jump lead.


  • After the faults have been rectified, trouble codes can be erased by using a Scan Tool connected to the data link connector (DLC) or as follows:
  • Switch ignition OFF.
  • Remove radio fuse No.39 (1OA) from underhood fusebox for 10 seconds minimum [4].
  • Reinstall fuse.
  • Repeat checking procedure to ensure no data remains in ECM fault memory.

Trouble code  identification

Flash code

OBD·II   codeFault location

Probable cause

PO, P2,uoRefer to OBD-11 trouble code tables
1Heated oxygen sensor (H02S) – front – circuit malfunctionWiring, H02S
4Crankshaft position (CKP) sensor 1 – range/performance problem/circuit malfunctionWiring, CKP sensor, valve timing, ECM
6Engine coolant temperature (ECT) sensor – circuit/voltage low/highWiring, ECT sensor, ECM
7Throttle position (TP) sensor – circuit/   voltage low/highWiring, TP sensor, ECM
7P1121Throttle position (TP) sensor – position lower than expectedTP sensor
7P1122Throttle position (TP) sensor – position higher than expectedTP sensor
8P1359Crankshaft position (CKP) sensor/engine speed (RPM) sensor – connector disconnectionWiring
8P1361Engine speed (RPM) sensor – intermittent signalRPM sensor
8P1362Engine speed (RPM) sensor- no signalWiring, RPM sensor, ECM
9P1381Camshaft position (CMP) sensor – intermittent signalCMP sensor
9P1382Camshaft position (CMP) sensor- no signalWiring, CMP sensor, ECM
10Intake air temperature (IAT) sensor- range/   performance problem/circuiUvoltage lowWiring, IAT sensor, ECM
12P1491Exhaust gas recirculation (EGR) system – valve lift insufficientWiring, EGR valve/position sensor, EGR   solenoid, hose leak/blockage, ECM
12P1498Exhaust gas recirculation (EGR) valve position sensor – voltage highWiring, EGR valve/position sensor, ECM
13P1106Barometric pressure (BARO) sensor- range/performance problemECM
13P1107Barometric pressure (BARO) sensor- circuiUvoltage lowECM
13P1108Barometric pressure (BARO) sensor- circuiUvoltage highECM
14Idle control system – malfunctionlAC valve, fast idle thermo valve, throttle body
14P1508Idle air control (lAC) valve – circuit failureWiring, lAC valve, ECM
17Vehicle speed sensor (VSS)- voltage lowWiring, VSS, ECM
20P1297Electrical load sensor – circuiUvoltage lowWiring, electrical load sensor, ECM
20P1298Electrical load sensor – circuiUvoltage highWiring, electrical load sensor, ECM
23Knock sensor (KS) – front- voltage lowWiring, KS, ECM
23Knock sensor (KS) – front – voltage highWiring, KS, ECM
30P1681AT to ECM – signal A – input lowWiring, TCM, ECM
30P1682AT to ECM – signal A – input highWiring, TCM, ECM
31P1686AT to ECM – signal B – input lowWiring, TCM, ECM
31P1687AT to ECM – signal B – input highWiring, TCM, ECM
41Heated oxygen sensor (H02S)- heater circuit malfunctionWiring, ECM
45Mixture too lean/richFuel system, front H02S, MAF sensor, mechanical fault
50Mass air flow (MAF) sensor – range/   performance problem/voltage low/highWiring open circuit, MAF sensor, ECM
50P1102Mass air flow (MAF) sensor – signal higher than expectedMAF sensor
50P1103Mass air flow (MAF) sensor – signal higher than expectedMAF sensor
53Knock sensor (KS) – rear- voltage low/   highWiring, KS, ECM
54P1336Crankshaft position (CKP) sensor 2 – intermittent signal interruptionCKP sensor
54P1337Crankshaft position (CKP) sensor 2 – no signalWiring, CKP sensor, ECM
61Heated oxygen sensor (H02S) -front- slow responseH02S, exhaust system
63Heated oxygen sensor (H02S) – rear- slow responseWiring, H02S, ECM
65Heated oxygen sensor (H02S) – rear- heater circuit malfunctionWiring, ECM
67Catalytic converter – efficiency below limitCatalytic converter, rear H02S
70AT·-Iock-up clutch not engaging/no gear shiftWiring, mainshaft speed sensor, countershaft speed sensor, lock-up control system, shift solenoid (SS) AlB, TCM
70P1660AT to TCM – data line failureWiring, ECM, TCM
70P1705AT- gear shift malfunctionWiring, range position switch, TCM
70P1705AT – lock-up clutch not engagingWiring, range position switch, TCM
70P1706AT – gear shift malfunctionWiring, range position switch, TCM
70P1706AT- lock-up clutch malfunctionWiring, range position switch, TCM
70P1753AT- lock-up clutch not engaging/   disengagingWiring, lock-up control solenoid A, TCM
70P1758AT – no gear shiftWiring, lock-up control solenoid B, TCM
70P1768AT – no gear shiftWiring, linear solenoid, TCM
70P1768AT – lock-up clutch not engagingWiring, linear solenoid, TCM
70P1786AT – poor gear shiftCommunication wire, TCM
70P1787AT – lock-up clutch malfunctionCommunication wire, TCM
70P1790AT- lock-up clutch not engagingWiring, TP sensor, TCM
70P1791AT – lock-up clutch not engagingWiring, VSS, TCM
70P1792AT – lock-up clutch not engagingWiring, ECT sensor, TCM
70P1794Automatic transmission – BARO signalWiring, ECM, TCM
71Cylinder No.1 – misfireWiring, injector, ignition system, mechanical fault
72Cylinder No.2 – misfireWiring, injector, ignition system, mechanical fault
73Cylinder No.3 – misfireWiring, injector, ignition system, mechanical fault
4Cylinder No.4 – misfireWiring, injector, ignition system, mechanical fault
75Cylinder No.5 – misfireWiring, injector, ignition system, mechanical fault
76Random misfirelgnition/fuei/EGR system, MAF sensor, lAC valve
80Exhaust gas recirculation (EGR) solenoid – insufficient flowEGR valve, hose/pipe leak or blockage
86Engine coolant temperature (ECT) sensor – range/performance problemECT sensor, cooling system
91Fuel tank pressure sensor- circuiUvoltage low/highWiring, pressure sensor, ECM
92Evaporative emission (EVAP) canister purge system – leak detected/incorrect flowWiring, hose leak/blockage, fuel tank/ pressure sensor, fuel filler cap, EVAP valve/bypass solenoid/flow switch,   EVAP two way valve, EVAP canister/vent valve, throttle body, ECM
92P1459Evaporative emission (EVAP) canister purge system – switch malfunctionWiring, flow switch, hose leak/blockage, ECM