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Home >> Mazda >> 2006 >> B4000 Base, Automatic >> Repair and Diagnosis >> Engine Performance >> Testing & Diagnosis >> Engine Symptom Troubleshooting - (3 Of 5) >> DTC Application Chart - Powertrain Control Module (Pcm) >> Intake Air Temperature (IAT) Sensor And Engine Coolant Temperature (ECT) / Cylinder Head Temperature (CHT) Sensor

Intake Air Temperature (IAT) Sensor And Engine Coolant Temperature (ECT) / Cylinder Head Temperature (CHT) Sensor

DTC P0112, P0113, P0117, P0118, P0125, P1112, P1116, P1117, P1285, P1288, P1289, P1290, P1299 DETECTION CONDITION & POSSIBLE CAUSES

DTC P0112, P0113, P0117, P0118, P0125, P1112, P1116, P1117, P1285, P1288, P1289, P1290, P1299 INTAKE AIR TEMPERATURE (IAT) SENSOR ENGINE COOLANT TEMPERATURE (ECT) SENSOR / CYLINDER HEAD TEMPERATURE (CHT) SENSOR
DETECTION CONDITION 
  • P0112 indicates the IAT sensor is less than the self-test minimum of 0.2V or 121°C (250°F).
  • P0113 indicates the IAT sensor is greater than the self-test maximum of 4.6V or -50°C (-58°F).
  • P0117 indicates the ECT sensor is less than the self-test minimum of 0.2V or 121°C (250°F).
  • P0118 indicates the ECT sensor is greater than the self-test maximum of 4.6V or -50°C (-58°F).
  • P0125 indicates the ECT sensor has not achieved the required temperature level to enter closed loop operating conditions within a specified amount of time after starting engine.
  • P1112 indicates the IAT sensor signal was intermittent during the comprehensive component monitor.
  • P1116 indicates the ECT sensor signal is out of self-test range (0.3-3.7 V).
  • P1117 indicates the ECT circuit was intermittently open or shorted while the engine was running.
  • P1285 indicates an engine overheat condition was sensed by CHT sensor.
  • P1288 indicates CHT sensor is out of self-test range (engine not at operating temp).
  • P1289 and P1290 indicate CHT sensor circuit malfunction (open or short).
  • P1299 indicates an engine overheat condition was detected by the CHT sensor and a FMEM strategy (fail safe cooling) was activated to cool the engine.
    NOTE:
    • Engine must be at normal operating temperature to pass KOEO and KOER self-test.
    • Ambient temperature must be above 10°C (50°F) to receive acceptable input from IAT.
POSSIBLE CAUSE 
  • Overheating condition (P1116)
  • Damaged harness (P1112, P1117)
  • Improper harness connection (P0112, P0113, P0117, P0118, P1289, P1290)
  • Grounded circuit in harness (P0112, P0117)
  • Damaged PCM (P0112, P1112, P0113, P1116, P0117, P1117, P0118, P1288, P1289, P1290)
  • Damaged ECT sensor (P1116, P0117, P1117, P0118)
  • Damaged CHT sensor (P1285, P1288, P1289, P1290)
  • Damaged IAT sensor (P0112, P1112, P0113)
  • Basic engine concerns.(P1285, P1299)
  • Engine cooling concerns.(P1285, P1299)
  • Insufficient warm-up time (P0125)
  • Low engine coolant level (P0125, P1116, P1117, P1285, P1288, P1299)
  • Poor thermostat operation (P1116)
  • Leaky or stuck open thermostat (P0125)
  • Damaged harness connector (P1112, P1116, P1117, P1288)
  • Open in ECT harness (P0118)
  • Grounded circuit in CHT harness (P1289, P1290)
  • Open circuit in CHT harness (P1289, P1290)
  • Short to power (P0113, P0118)
  • Open in IAT harness (P0113)
  • CHT sensor concerns (P1285)
HINT  IAT Sensor Description 
  • Thermistor type (passive) sensor.
  • Provides air temperature information to powertrain control module (PCM) which uses the information as a correction factor in the calculation of fuel, spark and mass air flow (MAF).
  • Resistance changes with temperature. Electrical resistance decreases as temperature increases, and increases as temperature decreases.

ECT / CHT Sensor Description 

  • Thermistor type (passive) sensor.
  • Provides engine coolant temperature information to PCM.
  • Resistance changes with temperature. Electrical resistance decreases as temperature increases, and increases as temperature decreases.
G04306901Courtesy of MAZDA MOTORS CORP.
G04306902Courtesy of MAZDA MOTORS CORP.
G04306903Courtesy of MAZDA MOTORS CORP.
G04306904Courtesy of MAZDA MOTORS CORP.
G04306905Courtesy of MAZDA MOTORS CORP.
CYLINDER HEAD TEMPERATURE SENSOR EXPECTED VALUES

Temperature CHT Sensor Values
°C °F COLD END HOT END Resistance (K ohms)
-40 -40 4.89 - 965.808
-30 -22 4.81 - 513.019
-20 -4 4.67 - 283.664
-10 14 4.45 - 162.584
0 32 4.14 - 96.255
10 50 3.73 - 59.175
20 68 3.26 - 37.387
30 86 2.74 -. 24.215
40 104 2.23 - 16.043
50 122 1.76 - 10.85
60 140 1.36 - 7.487
70 158 1.04 - 5.268
80 176 0.79 3.99 3.775
85 185 0.69 3.86 3.215
90 194 0.60 3.71 2.75
95 203 0.53 3.56 2.361
100 212 0.46 3.41 2.034
110 230 - 3.07 1.523
120 248 - 2.74 1.155
130 266 - 2.41 0.8866
140 284 - 2.10 0.6891
150 302 - 1.81 0.5417
160 320 - 1.55 0.4301
170 338 - 1.33 0.3449
180 356 - 1.13 0.2791
190 374 - 0.96 0.2278
200 392 - 0.82 0.1875
210 410 - 0.70 0.155
220 428 - 0.60 0.130
230 446 - 0.51 0.109
240 464 - 0.44 0.092
250 482 - 0.35 0.078
260 500 - 0.33 0.067
INTAKE AIR TEMPERATURE & ENGINE COOLANT TEMPERATURE SENSOR SPECIFICATIONS

Ambient Temperature (IAT/ECT PID) Resistance PCM 38/39 (signal) IAT V/ECT V PCM 91 (GND)
°C °F kΩ V V
120 248 1.18 0.27 Below 1.0
110 230 1.55 0, 35
100 212 2.07 0.46
90 194 2.80 0.60
80 176 3.84 0.78
70 158 5.37 1.02
60 140 7.70 1.33
50 122 10.97 1.70
40 104 16.15 2.13
30 86 24.27 2.60
20 68 37.30 3.07
10 50 58.75 3.51
DTC P0112, P0113, P0117, P0118, P0125, P1112, P1116, P1117, P1285, P1288, P1289, P1290, P1299 DIAGNOSTIC PROCEDURE

DTC P0112, P0113, P0117, P0118, P0125, P1112, P1116, P1117, P1285, P1288, P1289, P1290, P1299 INTAKE AIR TEMPERATURE (IAT) SENSOR ENGINE COOLANT TEMPERATURE (ECT) SENSOR / CYLINDER HEAD TEMPERATURE (CHT) SENSOR
STEP INSPECTION ACTION
1
  • Was the PCM quick test performed?
 Yes For DTC P1116or P1288: Go to next step. For DTC P1285: Go to step 4. For KOEO or KOER DTC P0113 or P0118: Go to step 6. For DTC P1289 or P1290: Go to step 10. For KOEO or KOER DTC P0112 or P0117: Go to step 11. For continuous memory (without KOEO and KOER DTCs) DTC P0112, P0113, P0117, P0118, P1112 or P1117: Go to step 14. For DTC P0125: Go to step 16. For DTC P1299: Go to step 17.
No Perform PCM Quick Test. See PCM QUICK TEST  .
2 DTC P1116, P1288: CHECK OPERATION OF ECT SENSOR/CHT SENSOR Yes Go to next step.
No Engine was not in closed loop operating conditions. Reset any other DTCs as necessary.
3 CHECK VREF CIRCUIT VOLTAGE AT TP SENSOR
  • Key OFF
  • Disconnect throttle position (TP) sensor connector.
  • Key on, Engine off (KOEO).
  • Measure voltage between VREF and SIG RTN at TP sensor harness connector.
  • Is the voltage between 4.0 and 6.0 V? 
 Yes Go to next step.
No See GENERAL PINPOINT TEST 1: VEHICLE REFERENCE VOLTAGE .
4 CHECK RESISTANCE OF TEMPERATURE SENSOR WITH ENGINE OFF
  • Key OFF.
  • Connect TP sensor.
  • Disconnect ECT /CHT sensor connector.
  • Measure resistance between ECT / CHT and SIG RTN at the ECT / CHT sensor harness connector.
  • Is resistance within specifications? 
 Yes For ECT / CHT sensor with a No Start, do not service DTC P1116 at this time. See SYMPTOM TROUBLESHOOTING CHART - ENGINE DRIVEABILITY .
For symptoms of cooling fan concerns, overheating and lack of heat, do not service DTC P1116 or P1288. Reset next DTC. If no other DTC exists, See SYMPTOM TROUBLESHOOTING CHART - ENGINE COOLING . All others: Go to next step.
No Replace suspect ECT / CHT sensor. See ENGINE COOLANT TEMPERATURE SENSOR REMOVAL / INSTALLATION or CYLINDER HEAD TEMPERATURE (CHT) SENSOR REMOVAL / INSTALLATION - 2.3L . Go to step 16.
5 CHECK RESISTANCE OF TEMPERATURE SENSOR WITH ENGINE RUNNING
NOTE:
  • Verify that engine is at operating temperature before taking ECT/CHT readings.
  • Key OFF.
  • Disconnect suspect temperature sensor.
  • Run engine at 2, 000 rpm for two minutes.
  • Measure resistance between ECT / CHT / IAT and SIG RTN at the sensor.
  • Is resistance within specifications? 
 Yes Replace PCM. See POWERTRAIN CONTROL MODULE (PCM) REMOVAL / INSTALLATION . Go to step 16.
No Replace ECT / CHT / MAF / IAT sensor. See ENGINE COOLANT TEMPERATURE SENSOR REMOVAL / INSTALLATIONCYLINDER HEAD TEMPERATURE (CHT) SENSOR REMOVAL / INSTALLATION - 2.3L or MASS AIR FLOW/INTAKE AIR TEMPERATURE (MAF/IAT) SENSOR REMOVAL / INSTALLATION . Go to step 18.
6 DTC P0118 OR P0113: CHECK VOLTAGE BETWEEN VREF AND SIG RTN
  • Key OFF.
  • Disconnect TP sensor.
  • Key on, engine off (KOEO).
  • Measure voltage between VREF and SIG RTN at the TP sensor harness connector.
  • Is the voltage between 4.0 and 6.0 V? 
 Yes See SYMPTOM TROUBLESHOOTING CHART - ENGINE COOLING . Go to next step.
No See GENERAL PINPOINT TEST 1: VEHICLE REFERENCE VOLTAGE .
7 SIMULATE OPPOSITE SIGNAL TO PCM
  • Key OFF.
  • Disconnect suspect temperature sensor connector.
  • Connect jumper wire between ECT/CHT/IAT and SIG RTN at the sensor connector.
  • Key on, engine off (KOEO).
    NOTE:
    • If a WDS or equivalent tester communication concern exists, remove jumper wire immediately and go to step 9.
  • Access ECT V/CHT V /IAT V PID.
  • Is ECT V or IAT V PID less than 0.2 V? 
 Yes Remove jumper wire. Replace suspect sensor. See ENGINE COOLANT TEMPERATURE SENSOR REMOVAL / INSTALLATIONGENERAL PINPOINT TEST 2: TACHOMETER OUTPUT (CTO) FAILURE or MASS AIR FLOW/INTAKE AIR TEMPERATURE (MAF/IAT) SENSOR REMOVAL / INSTALLATION . Go to step 18.
No Remove jumper wire. Go to next step.
8 CHECK TEMPERATURE SENSOR SIGNAL AND SIG RTN CIRCUITS FOR OPEN IN HARNESS
  • Key OFF.
  • Disconnect PCM.
  • Disconnect suspect temperature sensor.
  • Install breakout box, leave PCM disconnected.
  • Measure resistance between ECT/IAT at sensor harness connector and PCM test pin 38 (ECT) or 66 (CHT) or 39 (IAT).
  • Measure resistance between SIG RTN at sensor harness connector and PCM test pin 91.
  • Is each resistance less than 5.0 ohms? 
 Yes Replace PCM. See POWERTRAIN CONTROL MODULE (PCM) REMOVAL / INSTALLATION . Go to step 18.
No Repair open circuit. Go to step 18.
9 CHECK TEMPERATURE SENSOR SIGNAL AND SIG RTN CIRCUITS FOR SHORT TO VREF IN HARNESS
  • Measure resistance between ECT / CHT / IAT at sensor harness connector and PCM test pin 90 (VREF).
  • Is the resistance greater than 10K ohms? 
 Yes Replace PCM. See POWERTRAIN CONTROL MODULE (PCM) REMOVAL / INSTALLATION .
No Repair short to VREF. Go to step 18.
10 DTC P1289 OR P1290: CHECK VOLTAGE OF CHT SENSOR
  • Key on, engine off (KOEO).
  • Access CHT V PID.
  • Is CHT V PID less than 0.2 V? 
 Yes Go to next step.
No Go to step 7.
11 DTC P0112 OR P0117: SIMULATE OPPOSITE SIGNAL TO PCM
  • Key OFF.
  • Disconnect suspect temperature sensor.
  • Key on, engine off (KOEO).
  • Access ECT V / CHT V / IAT V PID.
  • Is PID greater than 4.6 V? 
 Yes Replace ECT / CHT / MAF / IAT sensor. See ENGINE COOLANT TEMPERATURE SENSOR REMOVAL / INSTALLATIONCYLINDER HEAD TEMPERATURE (CHT) SENSOR REMOVAL / INSTALLATION - 2.3L or MASS AIR FLOW/INTAKE AIR TEMPERATURE (MAF/IAT) SENSOR REMOVAL / INSTALLATION . Go to step 18.
No Go to next step.
12 CHECK VREF CIRCUIT VOLTAGE TO TP SENSOR
  • Key OFF.
  • Disconnect TP sensor.
  • Key on, engine off (KOEO).
  • Measure voltage between VREF and SIG RTN at TP sensor harness connector.
  • Is the voltage between 4.0 and 6.0 V? 
 Yes There is sufficient VREF voltage. Reconnect TP sensor connector. Go to next step.
No Reconnect TP sensor connector. See GENERAL PINPOINT TEST 1: VEHICLE REFERENCE VOLTAGE .
13 CHECK SIGNAL CIRCUIT FOR SHORT TO GROUND IN HARNESS
  • Key OFF.
  • Disconnect suspect temperature sensor.
  • Install breakout box, leave PCM disconnected.
  • Measure resistance between the following PCM test pins:
    • - 38 (ECT) or 66 (CHT) or 39 (IAT) and 24 (PWR GND)
    • - 38 (ECT) or 66 (CHT) or 39 (IAT) and 91 (SIG RTN)
  • Is each resistance greater than 10K ohms? 
 Yes Replace PCM. See POWERTRAIN CONTROL MODULE (PCM) REMOVAL / INSTALLATION . Go to step 18.
No Repair short circuit. Go to step 18.
14 DTCS P0112, P1112, P0113, P0117, P1117 OR P0118, P1289, P1290: INTERMITTENT CHECK
  • Key on, engine off (KOEO).
  • Monitor the ECT V or CHT V or IAT V PID.
  • While observing the PID, perform the following:
    • - Tap on sensor to simulate road shock
    • - Wiggle sensor connector
  • Is there any large change In the temperature reading? 
 Yes Disconnect and inspect connectors. If OK, replace sensor. See ENGINE COOLANT TEMPERATURE SENSOR REMOVAL / INSTALLATIONCYLINDER HEAD TEMPERATURE (CHT) SENSOR REMOVAL / INSTALLATION - 2.3L or MASS AIR FLOW/INTAKE AIR TEMPERATURE (MAF/IAT) SENSOR REMOVAL / INSTALLATION . Go to step 16.
NOTE:
  • For continuous DTCs P1112 and P1117, See comprehensive component monitor drive cycle.

See DRIVE CYCLES .
No Go to next step.
15 CHECK ENGINE WIRING HARNESS
  • Key ON.
  • While observing the ECT V or CHT V or IAT V PID, perform the following:
    • - Hold vehicle harness close to sensor connector. Wiggle, shake and bend small sections of wiring harness while working toward PCM
  • Is there any change in the temperature reading? 
 Yes Isolate fault and repair as necessary. Go to step 18.
NOTE:
  • For continuous DTCs P1112 and P1117, See comprehensive component monitor drive cycle.

See DRIVE CYCLES .
No Go to step 18.
16 DTC P0125 INDICATES EXCESSIVE TIME TO ENTER CLOSED LOOP FUEL CONTROL
  • Check engine coolant level.
  • Is coolant level fill correct? 
 Yes See SYMPTOM TROUBLESHOOTING CHART - ENGINE COOLING .
No Fill to proper level.
NOTE:

See DRIVE CYCLES . Go to step 18.
17 DTC P1299 INDICATES AN ENGINE OVERHEAT CONDITION OCCURRED
  • Check engine coolant level.
  • Is coolant level fill correct? 
 Yes See COOLING SYSTEM PINPOINT TEST 2: ENGINE OVERHEATS .
No See COOLING SYSTEM PINPOINT TEST 1: LOSS OF COOLANT .
18 VERIFY TROUBLESHOOTING OF DTCs COMPLETED
  • Make sure to connect all disconnected connectors.
  • Clear DTCs from PCM memory using WDS or equivalent tester.
  • Perform PCM Quick Test.
  • Is same DTC present? 
 Yes Replace PCM. See POWERTRAIN CONTROL MODULE (PCM) REMOVAL / INSTALLATION . Repeat PCM quick test.
No If any other DTC is present, go to applicable DTC inspection. See DIAGNOSTIC TROUBLE CODE (DTC) INDEX - POWERTRAIN CONTROL MODULE (PCM) . If no DTC is present, troubleshooting complete.
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